U.S. patent application number 12/673401 was filed with the patent office on 2012-05-24 for respiratory system.
This patent application is currently assigned to PLASTIFLEX BELGIUM. Invention is credited to Jon Richard Bedford, Malcolm Graham James, Neil Anthony Kaye, Jeno Kurja, Rik Julia Raoul Langerock.
Application Number | 20120125333 12/673401 |
Document ID | / |
Family ID | 40040013 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120125333 |
Kind Code |
A1 |
Bedford; Jon Richard ; et
al. |
May 24, 2012 |
RESPIRATORY SYSTEM
Abstract
The present invention relates a modular respiratory system to
which different parts can be added in a convenient way enabling
such upgraded respiratory system to deliver the most comfortable
respiratory conditions at an acceptable cost of ownership.
Inventors: |
Bedford; Jon Richard; (West
Yorkshire, GB) ; James; Malcolm Graham; (West
Yorkshire, GB) ; Kaye; Neil Anthony; (New South
Wales, AU) ; Kurja; Jeno; (Aerdenhout, NL) ;
Langerock; Rik Julia Raoul; (Merelbeke, BE) |
Assignee: |
PLASTIFLEX BELGIUM
Paal-Beringen
BE
|
Family ID: |
40040013 |
Appl. No.: |
12/673401 |
Filed: |
August 14, 2008 |
PCT Filed: |
August 14, 2008 |
PCT NO: |
PCT/EP2008/060727 |
371 Date: |
January 27, 2012 |
Current U.S.
Class: |
128/203.25 ;
128/203.26; 128/204.17; 128/204.18; 128/204.21; 128/205.12;
29/527.1 |
Current CPC
Class: |
A61M 2205/3584 20130101;
A61M 16/06 20130101; A61M 16/0816 20130101; A61M 2205/3592
20130101; A61M 16/1095 20140204; A61M 16/108 20140204; A61M
2205/3569 20130101; A61M 16/0875 20130101; A61M 16/109 20140204;
A61M 2205/3561 20130101; H05B 2203/019 20130101; A61M 2205/3633
20130101; A61M 16/0051 20130101; A61M 2205/3653 20130101; A61M
2205/3613 20130101; A61M 2016/0027 20130101; A61M 16/024 20170801;
A61M 2016/103 20130101; A61M 2016/1025 20130101; A61M 2205/3368
20130101; A61M 16/1075 20130101; A61M 16/16 20130101; A61M 2205/502
20130101; F16L 53/38 20180101; A61M 2016/0039 20130101; H05B
2203/02 20130101; A61M 16/161 20140204; Y10T 29/4998 20150115; H05B
3/58 20130101 |
Class at
Publication: |
128/203.25 ;
128/204.17; 128/204.18; 128/203.26; 128/205.12; 128/204.21;
29/527.1 |
International
Class: |
A61M 16/16 20060101
A61M016/16; B29C 49/00 20060101 B29C049/00; A62B 23/02 20060101
A62B023/02; A61M 16/06 20060101 A61M016/06; F24J 3/00 20060101
F24J003/00; A61M 16/00 20060101 A61M016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 14, 2007 |
EP |
07114350.7 |
Sep 12, 2007 |
EP |
07116251.5 |
Nov 30, 2007 |
EP |
07122033.9 |
Mar 25, 2008 |
EP |
08153243.4 |
Mar 25, 2008 |
EP |
08153245.9 |
Claims
1. A conduit for use in a respiratory system for supplying a
breathable gas from a flow generator (12) to a patient interface
(43), the conduit comprising a hose (36, 38, 50, 52, 54)
connectable between two parts of a respiratory system, a heating
element (37) associated with the hose (36, 38, 50, 52, 54) provided
for heating the breathable gas under control of a controller (11)
of the respiratory system, characterized in that the heating
element comprises at least one negative temperature coefficient
component (22).
2. A conduit according to claim 1, characterized in that the at
least one negative temperature coefficient component (22) is
provided over substantially the entire length of the hose (36, 38,
50, 52, 54).
3. conduit according to claim 2, characterized in that the heating
element (37) is a cable construction in which the at least one
negative temperature coefficient component (22) is
incorporated.
4. A conduit according to claim 3, characterized in that the cable
construction is a co-axial cable construction which comprises two
electrical wires (20, 21), one of which being a heating wire (21)
and the other being provided for feedback purposes, the two
electrical wires (20, 21) being separated by the at least one
negative temperature coefficient component (22).
5. A conduit according to claim 3, characterized in that the cable
construction is a co-axial cable construction which comprises two
heating wires (21), the two heating wires (21) being electrically
connected to each other at a first end and being connected to a
power supply at a second end, the cable construction further
comprising a coating comprising the at least one negative
temperature coefficient component (22) and surrounding said two
heating wires (21), and an additional electrical wire (20)
surrounding the coating.
6. A conduit according to claim 3, characterized in that the cable
construction is provided in a wall of the hose (38, 50).
7. A conduit according to claim 6, characterized in that the cable
construction is inserted into a helical wire groove (40) of the
hose (38).
8. A conduit according to claim 3, characterized in that said cable
construction is wound like a spring and provided for being
removably inserted into said hose (36).
9. A method for manufacturing a conduit for use in a respiratory
system for supplying a breathable gas from a flow generator (12) to
a patient interface (43), wherein in a first step a blowmoulded
tube (38) is formed comprising at least one helical wire groove
(40) on the exterior or interior surface of the tube (38) in a
second step at least one wire (20, 21, 37) is inserted in at least
one of the at least one wire groove (40).
10. A method according to claim 9, characterized in that in the
first step multiple parallelly extending helical wire grooves (40)
are formed on the exterior or interior surface of the tube
(38).
11. A method according to claim 10, characterized in that at least
two of the multiple parallelly extending helical wire grooves (40)
are formed with a different pitch.
12. A method according to claim 10, characterized in that in the
second step the at least one wire (20, 21, 37) is inserted in one
of the helical wire grooves (40).
13. A method according to claim 9, characterized in that in an
additional step an additional inner layer is extruded at the inside
of the tube (38) for forming a smooth bore.
14. A method according to claim 9, characterized in that in that in
an additional step an additional layer is extruded at the outside
of the tube (38) for closing the at least one wire groove (40).
15. A conduit for use in a respiratory system for supplying a
breathable gas from a flow generator (12) to a patient interface
(43), the conduit comprising a multipitch hose (50) connectable
between two parts of the respiratory system, the multipitch hose
(50) having an outer wall comprising at least two parallelly
extending helical ribs (16, 17), at least one of the helical ribs
16 holding at least one wire (20, 21, 37).
16. A conduit according to claim 15, characterized in that at least
one of the helical ribs (17) is empty.
17. A conduit according to claim 15, characterized in that the at
least one wire (20, 21, 37) is a co-axial cable construction which
comprises a negative temperature coefficient component or a
positive temperature coefficient component.
18. A respiratory system comprising a humidifier system (41), the
humidifier system (41) comprising an inlet for taking in a
breathable gas and a humidification chamber (53) connected to the
inlet for heating and humidifying the breathable gas before
delivery to a patient, characterized in that the respiratory system
further comprises a pre-conditioning system (52, 55) for
pre-conditioning the breathable gas before entry into the
humidification chamber (53) in a controlled manner.
19. A respiratory system according to claim 18, characterized in
that the pre-conditioning system (52, 55) comprises a temperature
control system for influencing the temperature of the breathable
gas at the inlet before entry into the humidification chamber
(53).
20. A respiratory system according to claim 18, characterized in
that the pre-conditioning system (52, 55) comprises a
humidification control system for influencing the humidity of the
breathable gas at the inlet before entry into the humidification
chamber (53).
21. A respiratory system according to claim 19, characterized in
that the temperature control system comprises an inlet hose (52)
connectable between the flow generator (12) and the inlet of the
humidification chamber (53) and in that the temperature control
system further comprises an inlet heating element associated with
the inlet hose (52) provided for heating the breathable gas before
entry into the humidification chamber (53) under control of a
controller of the respiratory system.
22. A respiratory system according to claim 18, characterized in
that the pre-conditioning system comprises an integrated humidifier
(55) of a flow generator (12) for heating and humidifying the
breathable gas before entry into the humidification chamber (53) in
a controlled manner.
23. A respiratory system according to claim 18, characterized in
that the pre-conditioning system (52, 55) comprises at least one
sensor for measuring the temperature and/or humidity of the ambient
air.
24. A respiratory system according to claim 18, characterized in
that the pre-conditioning system (52, 55) comprises at least one
dewpoint system for determining the dewpoint of the breathable
gas.
25. A respiratory system according to claim 18, characterized in
that at least part of the humidifier system (52, 55) is thermally
isolated from ambient conditions.
26. A respiratory system comprising a humidifier system (41), the
humidifier system comprising an inlet for taking in a breathable
gas, a humidification chamber (53) connected to the inlet for
heating and humidifying the breathable gas before delivery to a
patient interface (43), a conduit connectable to the humidifier
system for supplying the breathable gas to the patient interface
(43) and a heating system associated with the conduit for heating
the breathable gas delivered from the humidifier system to the
patient interface, the heating system comprising a heating element
in communication with a controller, characterized in that the
heating system comprises at least one dewpoint system for
determining the dewpoint of the breathable gas and being in
communication with the controller, which is provided for
controlling the heating element in response to a dewpoint value
determined by the at least one dewpoint system.
27. A humidifier system according to claim 26, characterized in
that the at least one dewpoint system is provided for determining
the dewpoint on a location near the humidification chamber
(53).
28. A humidifier system according to claim 26, characterized in
that the at least one dewpoint system is provided for determining
the dewpoint on a location near the patient interface.
29. A humidifier system according to claim 26, characterized in
that at least part of the humidifier system is thermally isolated
from ambient conditions.
30. A cuff (9) removably connectable between two parts of a
respiratory system, the cuff (9) comprising a passage for a
breathable gas flowing in the respiratory system, characterized in
that the cuff (9) comprises at least one integrated sensor (4) for
measuring respiratory care parameters of the breathable gas.
31. A cuff according to claim 30, characterized in that the at
least one sensor (4) is provided in the passage of the cuff
(9).
32. A cuff according to claim 30, characterized in that the cuff
(9) further comprises at least one communication module for
communicating with a patient interface (43) or a controller (11) of
the respiratory system.
33. A cuff according to claim 30, characterized in that the
removable connection of the cuff (9) to the other parts of the
respiratory system is provided in that the cuff (9) comprises first
cooperating means, provided to click on a first part of the
respiratory system, and second cooperating means, provided to click
on a second part of the respiratory system.
34. A respiratory mask (44) for use in a respiratory system,
provided for supplying a breathable gas from a conduit to a
patient, characterized in that the respiratory mask (44) comprises
a system for reducing condensation (45, 47, 48, 49) inside the
mask.
35. A respiratory mask according to claim 34, characterized in that
said condensation reduction system comprises a heating element (45)
provided for heating the breathable gas.
36. A respiratory mask according to claim 35, characterized in that
said heating element (45) is provided for heating the breathable
gas under control of a controller of the respiratory system.
37. A respiratory mask according to claim 35, characterized in that
said heating element (45) comprises a positive temperature
coefficient material or a negative temperature coefficient
material.
38. A respiratory mask according to claim 35, characterized in that
said heating element (45) is a heater mesh.
39. A respiratory mask according to claim 35, characterized in that
said heating element (45) is detachable from the mask.
40. A respiratory mask according to claim 35, characterized in that
said heating element (45) is provided for retrieving heat from the
body of the patient.
41. A respiratory mask according to claim 34, characterized in that
at least one sensor is incorporated in said mask for measuring at
least one respiratory care parameter.
42. A respiratory mask according to claim 34, characterized in that
said condensation reduction system comprises a thermally insulating
system (47, 48, 49) on said mask for insulating at least part of
said mask from ambient conditions.
43. A respiratory mask according to claim 42, characterized in that
the respiratory mask has a double wall (47, 48) formed by an outer
layer (48) and an inner layer (47) enclosing a sealed cavity (49),
forming said thermally insulating system.
44. A respiratory mask according to claim 43, characterized in that
the cavity (49) is a vacuum or is filled with a thermal insulating
material.
45. A respiratory system comprising at least the following parts: a
flow generator (12) for pressurizing a breathable gas a gas
conducting system for supplying the breathable gas from the flow
generator to a patient interface (43), the patient interface (43)
for supplying the breathable gas received from the gas conducting
system to a patient, characterized in that said respiratory system
is a modular respiratory system in which said gas conducting system
comprises a plurality of gas conducting parts, the gas conducting
parts being removably connectable to each other, the flow generator
12 and/or the patient interface (43).
46. A modular respiratory system according to claim 45,
characterized in that said plurality of gas conducting parts
comprises at least two interconnectable shorter conduit sections
(8) together forming a longer conduit section.
47. A modular respiratory system according to claim 45,
characterized in that one of said gas conducting parts is a
humidifier system (41) for heating and humidifying said breathable
gas before delivery to the patient, said humidifier system being
removably connectable between two other gas conducting parts of the
respiratory system.
48. A modular respiratory system according to claim 47,
characterized in that at least part of said humidifier system is
thermally insulated from ambient conditions.
49. A modular respiratory system according to claim 45,
characterized in that said gas conducting system comprises at least
one cuff (9) according to any one of claims 30-33.
50. A modular respiratory system according to claim 45,
characterized in that said gas conducting system further comprises
a controller section (11) provided for controlling respiratory care
parameters of the respiratory system.
51. A modular respiratory system according to claim 50,
characterized in that said controller section (11) comprises a
passage for the breathable gas flowing in the respiratory system,
and in that the controller section comprises at least one
integrated sensor in the passage for measuring respiratory care
parameters of the breathable gas.
52. A respiratory system according to claim 50, characterized in
that the controller section is provided to be independent of the
respiratory system.
53. A respiratory system according to claim 45, characterized in
that the respiratory system further comprises a human machine
interface (5) for setting values in a controller of the respiratory
system, thereby controlling respiratory care parameters of the
breathable gas.
54. A respiratory system according to claim 53, characterized in
that said human machine interface (5) is removably connectable to
any part of the respiratory system.
55. A respiratory system according to claim 45, characterized in
that at least part of the respiratory system comprises a
thermochromic material.
56. A respiratory system according to claim 45, characterized in
that at least part of the respiratory system comprises an anti
microbial treated material.
Description
TECHNICAL FIELD
[0001] The present invention relates to a respiratory system for
enhancing respiratory care patient comfort and compliance. The
respiratory apparatus of the present invention can be used for
humans as well as for veterinary purposes.
BACKGROUND ART
[0002] During respiratory care treatments a respiratory gas is
delivered to the patient. However, as soon as the respiratory care
treatment has started, potential side effects often arise which are
not due to the original root cause for which the external
respiratory assistance was needed in the first place.
[0003] As an example, but not limited to, serves the case of a
patient which is diagnosed with Obstructive Sleep Apnoea (OSA). In
OSA patients, the tongue and uvula partly or completely block air
from moving down the throat to the lungs. During Continuous
Positive Airway Pressure (CPAP) treatment an air flow is delivered
to the patient, allowing air to pass down the throat of the patient
to the lungs. Due to the high air flow rates, the airways are not
able to deliver sufficient heat and moisture. The result is that
the airways lose moisture and finally will show symptoms like
drying of the upper airways and infections such as dry nose, dry
throat, headache, painful chest, damage of weak tissue around nose
entry, bleeding nose, dry and damaged lips, infections of nose,
throat and sinus. In order to avoid these side effects the air flow
is usually heated and humidified before being delivered to the
patient.
[0004] As the heated and humidifier air travels along the conduit,
some heat is lost to the air outside of the conduit resulting in
condensation of the breathable gas. In order to avoid condensation
within the hose of the conduit, the hose usually comprises a
heating element provided for heating the breathable gas,
counteracting the heat lost along the length of the hose.
Conventional electrically heated hoses make use of a heating
element in the form of a resistance wire. In order to provide the
heating element with the right heating the hose usually comprises
one or more sensors to measure the temperature of the breathable
gas, this information being provided back to a controller which is
associated with the heating element. This is for instance described
in WO-A-2006019323. The use of additional separate sensors is not
always desired. In order to overcome the use of additional sensors,
U.S. 2003059213 describes to use a heater element in the form of an
electrical resistance heater exhibiting a positive temperature
behaviour. The resistance of a positive temperature coefficient
(PTC) material increases markedly once it reaches a threshold
temperature. A problem with PTC materials is that upon overheating
they melt down. So overheating of the resistance, which may occur,
causes permanent damage and the whole conduit has to be
replaced.
[0005] Literature references indicate that for CPAP therapy the
optimal temperature and humidity of the air are 30.degree. C.
containing 95% relative humidity or about 30 mg water per liter of
air absolute humidity. Literature references further indicate that
for ventilation the optimal temperature and humidity of the air are
37.degree. C. containing 100% relative humidity or about 44 mg
water per liter of air (absolute humidity).
[0006] The mentioned ideal absolute humidity and temperature are
important parameters that will determine the comfort of the
ventilated patient, reduce the unwanted side effects of the therapy
and hence contribute to the compliance of the patient. However,
tests prove that neither of the tested humidifier systems, when
operated under normal ambient conditions, i.e. normal ambient
temperature, or challenged ambient conditions, i.e. low ambient
temperature, are able to deliver the required optimal setting for
temperature and humidity but stay well below this optimal setting.
By increasing the temperature of the water reservoir of the
humidification chamber of the humidifier system, a headspace is
created that is warmer and more humid. However, the maximum
temperature of the humidification chamber is restricted since, at
too high temperatures, the air flow will contain a too high amount
of moisture that, once passing through the outlet hose and being
cooled down by ambient temperature, will start to condensate in the
outlet hose, i.e. the hose connecting the humidifier system and the
patient interface. Condensation is a very undesirable phenomenon in
ventilation and CPAP therapy. Condensation happens when the ambient
temperature cools the outlet air, i.e. the air leaving the
humidifier system, down below its dewpoint temperature. This can
happen when the ambient temperature is lower than the dewpoint
temperature of the breathable gas. By condensation, water is
removed from the airflow and as a result, the dewpoint will
decrease. Equilibrium is reached when the outlet air flow is cooled
down to its new dewpoint, which is ambient temperature.
[0007] To try and solve this issue, heated outlet conduits were
developed to counteract the cooling effect of the ambient
temperature and to maintain or increase temperature in the outlet
air over the length of the outlet conduit. The ultimate goal is to
have a temperature at the outlet of the hose that is still higher
than the dewpoint despite the cooling effect of the ambient
conditions. F&P HC 600 with Thermosmart.RTM. technology is
considered the benchmark in humidifier systems. This machine was
able to increase outlet temp and avoid condensation by
significantly increasing the temperature of the outlet air.
However, due to the heating relative humidity dropped and more
importantly, the machine was not able to deliver the optimum
absolute humidity of 30 mg water/liter air necessary to maximize
patient comfort. This drills down to the basic property of a
humidifier system that, in essence, was not able to deliver
sufficient absolute humidity to the air flow coming into the
reservoir due to the restricted maximum temperature. Due to the
restricted maximum temperature, the water bath can transfer a
limited amount of humidity depending on the heat capacity of the
water at that maximum temperature.
[0008] It is of utmost importance that this outlet air does not
cool down to avoid condensation. In extreme conditions (cold
ambient temperature), the inlet air has a lower capacity to hold
water compared to high ambient temperature inlet air. As such, this
cold air will extract energy from the heated humidifier, thereby
reducing its efficiency to maximize humidity uptake in the
humidifier and thereby reducing the dewpoint of the outlet air. A
reduced dewpoint means less absolute humidity so less comfort for
the patient. In case of a heated outlet hose, temperature can be
increased but humidity will be sub-optimal due to restrictions on
the temperature of the humidifier and the limited capacity of the
inlet air to hold moisture. In particular, the heated outlet hose
does help to maintain or increase temperature of the air flow
coming out of the humidifier chamber, thereby contributing to
reducing the risk for condensation, but the heated hose does not
contribute to increasing the absolute humidity of the airflow
delivered to the patient. As a consequence, even the F&P
benchmark 600 series with HH is not able to provide the 30 mg
water/liter of air (as claimed in the product literature),
especially in challenged conditions (cold ambient temperature).
[0009] Another problem arises when heated and humidified air
leaving the humidification chamber is passed through an inspiratory
hose versus a respiratory mask. The air breathed out by the patient
is passed through an expiratory hose back to the humidification
chamber. However, because of the high amount of moisture of the air
and because of the temperature difference between the ambient
temperature and the temperature of the air delivered to the patient
and the air breathed out by the patient, the air is likely to start
to condensate in the hoses and the respiratory mask.
[0010] Previous attempts to avoid the problem of condensation all
involved heating the gases in the inspiratory hose or in the
expiratory hose. The mask is however exposed to the highest
concentration of moisture and greatest temperature differences and
thus has the highest risk to the occurrence of condensation.
[0011] Another problem with current respiratory systems is that
they are very costly. Because most parts of the respiratory system
are integrated and fixedly attached to one another, practically the
whole system needs to be replaced in case there is damage to one or
more of the respiratory parts. This results in very high
replacement costs for the patient.
[0012] Moreover, the current respiratory systems offer few
flexibility to the patient. Because most of the parts are fixedly
attached to one another, it is difficult to upgrade the system once
therapy has started. Another problem is that the patient is not
able to adjust the settings, within clinical limits, such that the
most comfortable conditions are achieved from a patient's
perspective.
[0013] The respiratory care parameters are pre-set by the doctor at
the moment of the diagnosis. However, because ambient conditions
may be different at home compared to clinical conditions, the same
results are not always achieved at home. It is therefore desirable
that a respiratory system is provided, which is on a long term cost
efficient for the patient, easily up-gradable, which enables the
patient and/or nursing staff to achieve the most comfortable
conditions in a convenient way ensuring maximum compliance at the
lowest possible cost of ownership. The comfortable conditions are
may be chosen within two limits. The most desirable conditions for
the specific respiratory therapy will not exceed the conditions
known to cause damage, like temperatures higher than 41.degree. C.
Alternatively, similar damage causing conditions can be defined for
other relevant respiratory related parameters, like pressure,
air-flow etc. which should not be exceeded. From a lower limit,
certain conditions can be defined causing discomfort, as an
example, but not limiting, like humidity levels which cause the
upper airways to dry causing bleeding noses, headaches etc.
Alternatively, similar discomfort causing conditions can be defined
for other relevant respiratory related parameters, like
temperature, pressure, air-flow etc.
DEFINITIONS
Absolute Humidity:
[0014] Definition: Absolute Humidity is the actual amount of water
vapor in a liter of gas [0015] One liter of gas at 37.degree. C.
contains 22 mg of water vapor. Its Absolute Humidity is therefore
22 mg/L. [0016] If we add more water vapor to this gas, its
Absolute Humidity will increase. [0017] Clinical Example: By the
time gases reach the lung, they have been warmed to 37.degree. C.
and contain 44 mg/L absolute humidity.
Relative Humidity
[0017] [0018] Definition: There is a limit to how much water vapor
a gas can hold at a certain temperature. Relative Humidity measures
how much water vapor a gas is holding compared to how much it can
hold at that temperature. [0019] One liter of gas and contains 22
mg of water vapor. At 37.degree. C., this gas can hold 44 mg of
water vapor, but it is only half full currently, with 22 mg. i.e.
50% Relative Humidity. [0020] If another 22 mg of water vapor is
added the gas will reach its maximum capacity to hold water vapor
and the Relative Humidity is now 100%. [0021] Clinical Example: The
mucociliary transport system works at its maximum rate when
inspired gases are conditioned to 37.degree. C., 100% RH. This
represents 44 mg water vapor per liter of gas.
Dewpoint
[0021] [0022] This is the temperature where a gas is 100% Relative
Humidity (full of water vapor). If a gas cools below this
temperature, water vapor is lost as condensation. [0023] Clinical
Example: the gas within a humidified breathing circuit is warmer
and holds more vapor than the surrounding air. Unless the
humidified gas is kept above its dewpoint by using for example a
heated wire breathing circuit, the gas will cool and the water
vapor will be lost as condensation.
DISCLOSURE OF THE INVENTION
[0024] It is a first aim of the invention to provide a heating
element which allows repeatable detection and reduction of
overheating inside of the conduit.
[0025] This first aim is achieved with a conduit showing the
technical characteristics of the first independent claim.
[0026] It is a second aim of the invention to provide a process for
manufacturing a conduit in which at least one wire can be inserted
in a simplified way.
[0027] This second aim is achieved with a manufacturing method
showing the technical steps of the second independent claim.
[0028] It is a third aim of the invention to provide a conduit in
which at least one wire may be incorporated in a cost-efficient
way.
[0029] This third aim is achieve with a conduit showing the
technical characteristics of the third independent claim.
[0030] It is a fourth aim of the invention to provide a respiratory
system which comprises humidifier system which is able to
approximate more closely the optimal settings of temperature and
humidity.
[0031] This fourth aim is achieved with a humidifier system showing
the technical characteristics of the fourth and/or fifth
independent claim.
[0032] It is a fifth aim of the invention to provide a re-usable
cuff which allows measurements of respiratory care parameters on
whatever location within the respiratory system.
[0033] This fifth aim is achieved with a cuff showing the technical
characteristics of the sixth independent claim.
[0034] It is a sixth aim of the invention to provide a respiratory
mask in which the occurrence of condensation of the breathable gas
inside the mask is avoided.
[0035] This sixth aim is achieved with a mask showing the technical
characteristics of the seventh independent claim.
[0036] It is a seventh aim of the invention to provide a
cost-efficient, upgradable respiratory system.
[0037] This seventh aim is achieved with a modular respiratory
system showing the technical characteristics of the eighth
independent claim.
[0038] Two or more of the mentioned aspects of the invention may be
combined or may be part of a further aspect of the invention. It is
for instance possible to incorporate the conduit according to a
third aspect of the invention into a modular respiratory system
according to an eighth aspect of the invention, to incorporate a
respiratory mask according to a seventh aspect of the invention
into a modular respiratory system according to an eighth aspect of
the invention, and so on.
[0039] In a first aspect of the invention, a conduit for use in a
respiratory system is proposed which comprises a hose, connectable
between two parts of a respiratory system, and a heating element,
provided for heating the breathable gas under control of a
controller, wherein the heating element comprises a negative
temperature coefficient ("NTC") component.
[0040] The resistance of a NTC material decreases once it reaches a
threshold temperature. Preferably, the NTC component is composed to
provide a threshold temperature at or just above the preferred
gases temperature. As a result, the heating elements, comprising
such a NTC component, can be used themselves as a control element
and eliminate the need for additional sensors or thermocouples to
measure and control the temperature of the breathable gas. In fact,
when the preferred gases temperature is reached, the resistance of
the NTC component will decrease. This information may then be
transferred to a controller which will decrease the power supply to
the heating element and as such, reduce the temperature of the
breathable gas.
[0041] Furthermore, the presence of the NTC component also allows
the heating element to detect and minimize locally overheating
inside the conduit in a repeatable manner. When overheating occurs
near the NTC component, for instance as a result of a hot spot of
the heating element, the resistance of the NTC component will
decrease rapidly in view of the logarithmic relationship between
the resistance of an NTC material and the temperature. This
information can be provided to a controller which can more rapidly
decrease the power supply to the heater element with respect to the
prior art, thereby avoiding permanent damage to the conduit.
[0042] Furthermore, analysis has shown that NTC components are less
prone to be permanently damaged than PTC materials. As a result,
the NTC component enables a repeatable detection and reduction of
overheating inside the conduit. Summarizing, the conduit according
to the first aspect of the invention comprises a heating element
which provides for heating and controlling of the temperature
within the hose of the conduit and for repeatably detecting and
reducing the occurrence of overheating spots on specific locations
within the hose.
[0043] The heating element with the NTC component may take any form
considered suitable by the person skilled in the art. Preferably,
one or more NTC components is/are provided over substantially the
entire length of the hose, such as for example a series of NTC
thermistors along the hose. This configuration allows detecting and
minimizing overheating over substantially the entire length of the
hose. From the moment there is, somewhere along the hose, a section
which is locally overheated, the resistance of the NTC component at
this section will decrease rapidly. This information can then be
provided back to a controller which can decrease the power supply
accordingly. A
[0044] Preferably, the heating element takes the form of a heating
cable in which an NTC component is incorporated. This type of
configuration is in particular suitable to detect and minimize hot
spots in the heating wire. Hot spots are short sections in the
heating wire which show a much lower resistance compared to the
surrounding sections. In the prior art, such a hot spot could
result in melting through of the hose wall. In this preferred
embodiment, if there is a hot spot somewhere along the heating
cable, the resistance of the NTC component will decrease enabling
reduction of the power supply before melting of the hose wall at
the hot spot occurs. This can further ensure the repeatability of
the overheating detection in the first aspect of the invention.
[0045] Preferably, the heating element forms a co-axial cable
construction which extends in longitudinal direction of the hose,
the cable construction comprising two electrical wires, one of
which being a heating wire and the other being provided for
feedback purposes, the two electrical wires being separated by the
negative temperature coefficient component. Such a co-axial cable
construction has the advantage that it has a very small diameter,
so that it can be associated with the hose in a number of different
ways, such as for instance in a rib in the wall of the hose, in a
wire groove at the inside of the hose or the outside of the hose,
wound like a spring.
[0046] In a second aspect of the invention a method for
manufacturing a conduit is proposed in which a heater wire can be
inserted in a wall of the hose in a simplified, fast and
cost-efficient way. The method comprises a first step in which a
blowmoulded tube is formed comprising at least one helical wire
groove on the exterior or interior surface of the tube and a second
step in which at least one wire is inserted in one or more of the
at least one wire groove. The forming blocks of the corrugator are
shaped in such a way that the at least one helical wire groove is
formed upon blowmoulding the tube. The wire can be a heating wire,
a communication wire, a combined heater and communication cable or
any other wire or cable.
[0047] Blowmoulded tubes or hoses may have a so-called corrugated
wall of protrusions alternating with recesses. These corrugations
may progress helically in longitudinal direction of the tube or
hose. Advantageously, the helical wire groove(s) can be formed by
the recesses in between such helical corrugations of such a
corrugated blowmoulded tube.
[0048] Alternatively, the tube may comprises a helical wire groove
with a different pitch with respect to that of the hose
corrugations (which do not necessarily have to be helical). The
pitch of the hose corrugations in general serves a different
purpose than that of the wire groove. In general, the pitch of the
hose corrugations is related to the strength and flexibility of the
hose, whereas the pitch of the wire groove is for instance related
to the amount of energy/heat which has to be transferred to the
fluid which is passed through the hose. The pitch of the wire
groove(s) determines the length of the wire that is inserted into
it. The higher the length of the wire is, the higher the cost of
the overall system. So it may be advantageous that the hose
corrugations and the wire groove(s) have a different pitch. In case
the pitch of the wire groove differs from that of the hose groove,
it is for instance possible to have a hose with high strength, i.e.
wherein the corrugated wall of the hose has a zero or small pitch,
combined with a cost-efficient hose in which not too much wire is
consumed, i.e. wherein the wire groove has a higher pitch.
[0049] The method according to the second aspect of the invention
can therefore provide in a cheaper conduit and in a reduction of
the overall weight of the conduit. Another advantage is that the
method according to the second aspect of the invention allows
manufacturing a hose in which at least one wire can be inserted,
with a simplified and automated process.
[0050] The pitch of the wire groove can be constant or can vary in
longitudinal direction of the hose. The latter is for instance done
in case a heater wire is inserted and an intensive heating is for
instance desired in the centre of the hose and a less intensive
heating is desired near the edges of the hose.
[0051] It is further possible to vary other properties of the
helical wire groove, such as the width and height of the wire
groove. The variation of these properties can for instance be used
to influence the accessibility of the at least one wire. By varying
the width of the helical wire groove for instance, the at least one
wire may be more or less positioned in the groove. Preferably, the
shape of the wire groove (in cross-section) is such that the at
least one wire is clamped within the wire groove. Varying the
diameter of the helical wire groove may for instance be desired in
case use is made of hoses with varying diameter, for instance for
use in hoses for CPAP systems where the diameter of the hose
changes versus the patient interface.
[0052] The at least one helical wire groove can be wound clockwise
or counter clockwise. One helical wire groove can be used to carry
multiple wires, whereas different wires can have different
purposes. One wire can for instance be used for heating the fluid
passing inside the hose in order to avoid condensation inside the
tube. Another wire can be used for carrying signals for
communication and power for the patient mask of the CPAP unit.
[0053] Preferably, the method according to the second aspect of the
invention is characterized in that in the first step multiple
helical wire grooves are formed on the exterior or interior surface
of the tube. Each of the wire grooves can be provided for carrying
one or more wires. Some of the wire grooves may not carry any
wires. Different wire grooves can have the same or a different
pitch. In this way different wire grooves can for instance be used
to carry wires which serve different purposes. A helical wire
groove for carrying heater wires will usually have a smaller pitch
than a helical wire groove for carrying communication wires.
Different wire grooves can also differ in width and height,
depending of the type and number of wires to be carried. Different
wire grooves can both be wound clockwise or counter clockwise or
one can be wound clockwise and the other counter clockwise. By
varying the relative position of the different wire grooves, it is
possible to provide the hose with more and less accessible wires.
Preferably, the different wire grooves extend parallelly, i.e. in a
dual, triple or multi-pitch configuration.
[0054] The method for manufacturing a conduit according to the
second aspect of the invention preferably comprises an additional
step in which an additional layer is extruded at the inside of the
tube for forming a smooth bore. A multilayer smooth bore hose
formed with the method according to the second aspect of the
invention has the advantage that a breathable gas passing through
the hose encounters less resistance compared to a tube with a
corrugated inner surface.
[0055] Preferably, the method according to the second aspect of the
invention further comprises an additional step in which an
additional layer is extruded at the outside of the tube for closing
the at least one wire groove and as such, encapsulate the at least
one wire which was inserted into the at least one wire groove. This
additional layer can cover the entire hose or can be applied to
only cover the wires.
[0056] In a third aspect of the invention a conduit for use in a
respiratory system for supplying a breathable gas from a flow
generator to a patient interface is proposed, the conduit
comprising a hose connectable between two parts of the respiratory
system, the hose being a multipitch hose comprising at least two
parallelly extending helical ribs and at least one of the ribs
holding at least one wire.
[0057] The conduit according to the third aspect of the invention
provides in an alternative simplified way of incorporating at least
one wire in the hose of a conduit. In fact these ribs can be
created directly from the extrusion machines, whereas the parallel
extending helical ribs have a different starting position on the
extruder. An alternative could be to make the conduit web as a
linear profile strip. In this form the wire if being used would
again be located within the profile. Then one or more profile
strips are wound in a helical form, as a second process, to produce
the conduit. This technique of manufacturing a flexible hose by
helically winding a web is known per se in the field of hose
manufacturing and therefore needs no further explanation here.
[0058] The conduit according to the third aspect of the invention
further has the advantage that the production speed of the conduit
can be increased and thus manufacturing costs may be reduced.
Another advantage is that the conduit may have a lower consumption
of expensive wire materials, since the pitch of the ribs can be
chosen.
[0059] The conduit according to the third aspect of the invention
further has the advantage that a large number of wires can be
integrated into the hose of the conduit in a fast and
cost-efficient way. This can be understood from the fact that more
than two helical ribs can be provided. By increasing the number of
ribs, the number of wires may be increased accordingly by a factor
relating to the number of pitches. Moreover, it is possible to
include more than one wire into one rib. As such, the conduit
according to the third aspect of the invention is in particular
suitable for holding at least 4 wires.
[0060] The at least one wire may be a heater wire, a communication
wire, or a combined cable construction as shown in FIGS. 1 and 2 or
any other wire or cable. Only one of the two (or more) helical ribs
may contain a wire, or both of the helical ribs may contain a wire.
One helical rib can be used to carry multiple wires, whereas
different wires can have different purposes. One wire can for
instance be used for heating the passing fluid inside the hose in
order to avoid condensation inside the tube. Another wire can be
used for carrying signals for communication and power for the
patient mask of the CPAP unit. The two helical ribs may serve
different functions. The first helical rib may carry heater wires,
whereas the second helical rib may carry communication wires. As a
result, the conduit according to the third aspect of the invention
may offer a greater number of functions if required, due to the
availability of more signal capacity.
[0061] The at least one wire may comprise a co-axial cable
construction which comprises a PTC or NTC component, provided for
detecting and reducing the occurrence of overheating within the
hose.
[0062] The pitch of the helical ribs can be constant or can vary in
longitudinal direction of the hose. The latter is for instance done
in case a heater wire is inserted and an intensive heating is for
instance desired in the centre of the hose and a less intensive
heating is desired near the edges of the hose. Each of the helical
ribs can be provided for carrying one or more wires. Some of the
ribs may not carry any wires. Different ribs can also differ in
width and height, depending of the type and number of wires to be
carried. The conduit may comprise more than two helical ribs.
[0063] The conduit according to the third aspect of the invention
may have a smooth inner layer, such that the breathable gas passing
through the tube encounters less resistance compared to the tube
with a corrugated inner surface.
[0064] In a fourth aspect of the invention a respiratory system is
proposed which comprises a humidifier system, the humidifier system
comprising an inlet for taking in a breathable gas and a
humidification chamber connected to the inlet for heating and
humidifying the breathable gas before delivery to a patient. The
respiratory system according to the fourth aspect of the invention
further comprises a pre-conditioning system for pre-conditioning
the breathable gas at the inlet before entry into the
humidification chamber in a controlled manner.
[0065] By preconditioning the breathable gas at the inlet before
entry into the humidification chamber in a controlled manner, the
performance of the respiratory system can be improved. In fact, by
pre-conditioning the breathable gas, the respiratory system will be
able to approximate more closely the optimal settings for
temperature and humidity. Because the ideal absolute humidity and
temperature are important parameters that can determine the comfort
of the ventilated patient and that can avoid unwanted side effects
as a result of the treatment, the respiratory system according to
the fourth aspect of the invention can also improve patient
comfort.
[0066] Because the pre-conditioning is done in a controlled manner
these optimal settings can be approximated independently from the
ambient conditions in which the respiratory system is operating,
i.e. in normal conditions, i.e. normal ambient temperatures, as
well as abnormal conditions, i.e. cold ambient temperatures.
Another advantage of pre-conditioning the breathable gas is that
the risk for condensation in the respiratory system may be further
reduced independently from the ambient conditions in which the
respiratory system is operating. This is because the design of the
humidification chamber can be better optimized for reaching optimum
humidity and temperature levels in the breathable gas, since
variations in the temperature and humidity levels at the inlet can
be largely cancelled out by the controlled pre-conditioning.
[0067] In a preferred embodiment of the respiratory system
according to the fourth aspect of the invention, the
pre-conditioning system comprises a temperature control system for
influencing the temperature of the breathable gas at the inlet
before entry into the humidification chamber.
[0068] The temperature control system preferably comprises an inlet
heating element, provided for heating the breathable gas before
entry into the humidification chamber, and a controller, provided
for controlling the inlet heating element. The pre-heated
breathable gas can be generated with any heating element considered
suitable by the person skilled in the art. The pre-heated
breathable gas can for instance be generated with a heating element
internal in the inlet hose of the humidifier system, a heating
element external to the inlet hose of the humidifier system, with a
heating element incorporated in the flow generator. The controller
may be any type of controller considered suitable by the person
skilled in the art, such as for example a controller which is
incorporated into the conduit of the respiratory system or an
independent controller. By pre-heating the inlet air, i.e. the air
entering the humidification chamber, in a controlled manner, the
temperature of the inlet air can be increased from ambient to a
certain setpoint, which can be maintained irrespective of changes
in ambient conditions.
[0069] An advantage of such a respiratory system is that it has a
higher capacity to hold humidity and is able to take up more
humidity from the humidifier. Another advantage of the respiratory
system according to the fourth aspect of the invention is that the
pre-heated breathable gas has a higher heat capacity, which results
in a reduction of the energy extraction from the humidifier and an
optimization of the efficiency of the humidifier.
[0070] In another preferred embodiment of the respiratory system
according to the fourth aspect of the invention, the
pre-conditioning system comprises a humidity control system for
influencing the humidity of the breathable gas at the inlet before
entry into the humidification chamber.
[0071] By pre-humidifying the inlet air, the humidity of the inlet
air is increased from ambient to a certain setpoint. The
humidification can be generated with any humidification element
considered suitable by the person skilled in the art. The
humidification can for instance be done by a second humidifier
system integrated in the flow generator. An advantage of such a
respiratory system is that the pre-humidified inlet air has a
higher humidity level, which results in a reduction of the energy
extraction from the humidifier and an optimization of the
efficiency of the humidifier.
[0072] The pre-conditioned breathable gas may be both pre-heated
and pre-humidified.
[0073] The pre-conditioning system may comprise any sensor
considered suitable by the person skilled in the art to control the
temperature and/or humidity of the breathable inlet gas. The
pre-conditioning system may comprise one or more of these
sensors.
[0074] The controller may for instance use the ambient air
temperature and/or the ambient air humidity, measured by at least
one sensor provided in the pre-conditioning system, to set the
inlet air temperature and/or to set the inlet air humidity. In this
way, the performance of the respiratory system is less dependant of
the ambient conditions and the optimal settings can be approximated
independently from the ambient conditions in which the respiratory
system is operating.
[0075] Instead of the ambient air sensors, or in addition thereto,
the controller may use a dewpoint system for determining the
dewpoint temperature of the breathable gas. The dewpoint system may
be any means considered suitable by the person skilled in the art.
The dewpoint system for example comprises two sensors, one for
measuring the temperature of the breathable gas, and one for
measuring the humidity level of the breathable gas, but the
dewpoint system may for instance also be a combined dewpoint
sensor. The dewpoint system may be placed on whatever location in
the respiratory system, preferably close to the inlet of the
humidification chamber of the humidifier system. By determining the
dewpoint temperature of the breathable gas, the temperature and
humidity of the breathable gas can be controlled in such a way that
its temperature stays well above its dewpoint temperature and well
above the ambient dewpoint temperature, such that condensation of
the breathable gas can be avoided.
[0076] In a fifth aspect of the invention a respiratory system is
provided, which comprises a humidifier system in which the
temperature of the outlet gas, i.e. the breathable gas leaving the
humidification chamber of the humidifier system, is controlled.
[0077] The respiratory system according to a fifth aspect of the
invention comprises a humidifier system which comprises an inlet
for taking in a breathable gas and a humidification chamber
connected to the inlet for heating and humidifying the breathable
gas. A conduit connects the humidifier system to the patient
interface. The humidifier system further comprises a heating
system, associated with the conduit and provided for heating the
breathable gas delivered from the humidifier system to the patient
interface. The heating system comprises a heating element and a
dewpoint system for determining the dewpoint of the breathable gas.
Both the dewpoint system and the heating element are in
communication with a controller of the respiratory system.
[0078] This respiratory system allows controlling the temperature
of the gas leaving the humidification chamber based on the dewpoint
temperature of the breathable gas. The dewpoint temperature is
provided back to a controller, which is in communication with a
heating element of the humidifier system. This system can be used
to set the temperature of the air leaving the humidification
chamber higher than the dewpoint temperature of the breathable gas
to avoid condensation of the breathable gas inside the conduit.
[0079] The dewpoint system for determining the dewpoint temperature
of the breathable gas can be provided for determining the dewpoint
on any location of the respiratory system considered suitable by
the person skilled in the art. The dewpoint system can for instance
by determined close to the humidification chamber or at a position
near the patient interface. Optionally, the respiratory system may
comprise multiple locations where the dewpoint is determined. By
determining the dewpoint at a first location near the
humidification chamber and a second location near the patient
interface, condensation inside the conduit can be further
reduced.
[0080] The dewpoint system can be any system considered suitable by
the person skilled in the art which allows determining the
dewpoint. The dewpoint system can for instance comprise a seperate
temperature and humidity sensor combined with a processor which,
based on predetermined tables, determines the dewpoint based on the
temperature and humidity measurements of the separate sensors. The
dewpoints sensor can for instance comprise an integrated dewpoint
sensor which directly determines the dewpoint and provides it back
to a controller.
[0081] Optionally, the humidifier system of the respiratory system
according to the fifth aspect of the invention may comprise
additional sensors, for instance pressure sensors, which allow
further control of the gas leaving the humidification chamber.
[0082] The dewpoint temperature of the breathable gas can
additionally be used to control any other heating elements of the
respiratory system considered suitable by the person skilled in the
art, such as a heating element connected to the hose connecting the
humidifier system and the patient interface. This allows further
reducing the risk to condensation within the conduit.
[0083] In a sixth aspect of the invention a cuff is proposed which
is removably connectable between two parts of a respiratory system.
The cuff according to a sixth aspect of the invention comprises a
passage for a breathable gas flowing in the respiratory system and
comprises at least one integrated sensor for measuring respiratory
care parameters of the breathable gas.
[0084] Because the cuff is removably connectable between two parts
of a respiratory system, it does not need to be thrown away
together with that part of the respiratory system that needs to be
replaced. For instance, in case the hose needs to be replaced, the
cuff which is connected to the hose can be re-used to connect to a
replacement hose. This results in reduced replacement costs.
[0085] Another advantage of the cuff according to a sixth aspect of
the invention is that, if a patient requires an upgrade of its
respiratory system, it does not necessarily need to replace its
complete conduit system. It may be sufficient to replace the cuff
with another cuff that comprises more or other sensors or more or
other integrated communications tools.
[0086] The cuff is in particular suited for use in a modular
respiratory system where two or more parts are removably
connectable to each other. Using modular technology means that the
patient can have more flexibility and patient enhancement at a
longer term reduced cost. If required the technology can be
enhanced and more reliable components can be used as the cuff cost
will be distributed over a number of users, and not just as a
single use consumable. The modular design will assist in
manufacturing and distribution. The different parts of the
respiratory system can be made on different location, even in
different countries. Another advantage is that the cuff allows the
user to select the best fit for their situation. Another advantage
of the cuff according to a sixth aspect of the invention is that
the cuff can be tailor made for one specific application or
treatment, without needing to replace the hose itself. Another
advantage is that the complex electronics for measuring and
controlling the respiratory care characteristics do not need to be
installed into the hose, but may be incorporated into the cuff,
which results in a reduction of long term costs for the user.
[0087] The cuff is designed in such a way that it can connect to
any part of the respiratory system, for instance a human machine
interface with a hose, two interconnecting hose sections, a
controller to a hose. The cuff can be positioned on any location
within the respiratory system. The cuff can for instance be located
directly onto the humidifier system or flow generator and be used
to measure parameters as temperature, airflow, and humidity of the
breathable gas. The cuff can be connected to the patient mask. This
means that the cuff can contain some mask technology such as
venting and pressure measurement, O2 concentrations, CO2
concentration, air flow rate. This allows a direct measurement and
control of all relevant measurement respiratory care parameters of
the breathable gas. In current respiratory systems, the control is
indirect and potentially complex, delayed, expensive and subject to
high level of signal noise. This is due to the fact that, in
current respiratory systems, the control of the system is usually
done by the unit. Usually, the unit, i.e. ventilator unit, positive
air pressure device, anesthesia unit, contains the measurement
instruments and electronics to control the relevant parameters, for
instance air flow, pressure, anesthetic gas concentration, oxygen
concentration, to monitor the patient's condition. However, when
the air flow exits the conduit, there is no direct measurement of
the air flow whereas the airflow might have decreased due to the
resistance level of the hose. This is similar for pressure.
Pressure is generated by the unit. However, no pressure is measured
near the patient. Pressure drop will occur over the hose but is not
measured directly. Due to the absence of measuring devices near the
patent interface, the units rely on indirect measurements, for
instance ambient temperature measurements, that are not localized
near the patient interface and as such, software needs to include
all kinds of compensation algorithms to control or adjust the
output of the unit. In some therapies, the expired air is conducted
back to the unit to perform measurements. However, due to the
absence of measuring devices near the patient interface, the units
rely on indirect and delayed measurements and as such, software
needs to include all kinds of compensation algorithms to control or
adjust the functioning of the unit. Because the cuff can be
connected directly onto the patient interface, signals are
generated at the right location and may be transferred directly to
the unit allowing accurate monitoring and control.
[0088] Preferably, the at least one sensor is located in the
passage of the cuff, such that it can directly measure any
characteristics of the breathable gas passing through. The at least
one sensor of the cuff can also be located somewhere else, for
instance in the wall of the cuff.
[0089] Preferably, the cuff is designed in such a way that it may
click on any part of the respiratory system. The click-on system
preferably works in conjunction with a compatible cuff on that part
of the respiratory system where it is attached to and which
incorporates single or multiple wire systems either integrated in
the hose construction or loosely or fixed inserted flat in the
conduit or attached to the outside of the hose. The communication
between the click-on cuff can also be done independent of the hose
by either loose connection wires or wireless transmission. The
benefit of this system is that the click-on cuff provides the
functionality needed to generate the signal at the patient
interface whereas the communication conduit carries the signal to
the independent control unit or ventilation unit. The click-on cuff
is designed for long time repeated use whereas the communication
conduit can be designed as a disposable product or as a reusable
product.
[0090] In a seventh aspect of the invention a respiratory mask is
proposed which comprises a condensation reduction system for
reducing condensation inside the mask. The respiratory mask can be
any type of respiratory mask, nose masks as well as face masks. The
mask can be made from hard or soft materials or a combination
thereof. The condensation reduction system can be an active system,
for example with an active heating element with which the
breathable gas in the mask can be heated to avoid condensation, or
a passive system, for example comprising insulation material to
passively avoid cooling down of the breathable gas is the mask, or
a combination of an active and a passive system.
[0091] According to a first embodiment of the respiratory mask
according to the seventh aspect of the invention, said condensation
reduction system comprises a heating element provided for heating
the breathable gas. By sufficiently heating the breathable gas
inside the gas, condensation of the gas within the mask can be
reduced.
[0092] The element system can be located on any position of the
mask. The heating element may for instance be attached to the
outside and/or the inside of the mask, or may be embedded in the
wall of the mask.
[0093] The heating element can be permanently integrated into the
mask or can be made detachable from the mask. A detachable heating
element has the advantage that it is re-usable, which results in
lower replacement costs for the patient. Preferably the heating
element comprises a heating part, preferably a heating mesh,
attached to the outside of the mask and/or to the inside of the
mask. The heating element may comprise an NTC (negative temperature
coefficient) or PTC (positive temperature coefficient) material.
Because the resistance of NTC and PTC materials changes with
changing temperature, these materials can be used in itself as
temperature sensors, controlling the temperature of the air.
Alternatively, the heating element may comprise independent
temperature sensors. The heating element can be constructed from
standard heating wire. The heating element can also retrieve heat
directly from the patient, so that a separate heat source can be
avoided.
[0094] Preferably, the heating element is controlled by a
controller of the respiratory system. The control is for instance
based on dewpoint measurements of the breathable gas, preferably at
a position near the patient's mask. By heating the breathable gas
to a temperature above its dewpoint temperature, condensation
inside the mask may be reduced. The control of the heating element
may be based on any other respiratory care parameters considered
suitable by the person skilled in the art. The use of a control has
the advantage that the performance of the mask can be made less
dependant on the ambient conditions.
[0095] The heating element can be controlled via an independent
controller or any system integrated controller. The controller can
connect to said mask via direct leads or terminal connections. The
controller can be connected to the mask via a cuff according to a
sixth aspect of the invention. The controller can utilize
electrical swivel connections either at the mask connection and/or
at the feed connection. These connection leads can be integrated
into the hose construction or can be independent flying leads. The
heating element may for instance be controlled via a hose with
integrated control wires. The leads can be integrated into the
inspiratory or expiratory hose.
[0096] In order to avoid contact between the heating system and the
respirated air, the heating element is preferably isolated from the
air. This may for instance be achieved by providing the heating
element inside a cavity inside the mask. The presence of a sealed
cavity inside the mask allows sterilization of the respiratory
mask. The heating element can have a variety of shapes adjusted to
the different shapes of the mask.
[0097] According to a second preferred embodiment of the
respiratory mask according to the seventh aspect of the invention,
said system comprises a thermally insulating system for thermally
insulating at least part of said mask from ambient conditions.
[0098] The insulating system provides for an improved insulation of
the moisturized inspiratory and expiratory air from the ambient
temperature, which results in a reduced occurrence of condensation
within the patients mask.
[0099] The insulating system may be any kind of insulating system
considered suitable by the person skilled in the art. The
respiratory mask may for instance comprise a thermally insulating
material which covers at least part of the respiratory mask.
[0100] Preferably, the respiratory mask has a double wall formed by
an outer layer and an inner layer, which provides for improved
isolation. Preferably, the inner and outer layers enclose a sealed
cavity. In order to reduce the thermal conductivity from outside
the mask to the inside of the mask, the sealed cavity preferably
comprises a vacuum or is filled with air or any other thermal
insulating material or material with low level of thermal
conductivity known to the person skilled in the art.
[0101] The respiratory mask may comprise both a heating system as
an insulating material. This type of mask provides in a further
reduction of condensation of breathable gas inside the mask.
[0102] In an eighth aspect of the invention a modular respiratory
system is proposed which comprises at least a flow generator, for
pressurizing a breathable gas, a gas conducting system, for
supplying the breathable gas from the flow generator to a patient
interface, and the patient interface for supplying the breathable
gas received from the gas conducting system to a patient. The
respiratory system is a modular system in which the gas conducting
system is formed by removably connecting multiple gas conducting
parts to each other.
[0103] Such a modular respiratory system results in a longer term
reduced cost for the patient. If one of the respiratory system
parts is damaged, it is not necessary to throw away the entire
respiratory system, but it is sufficient to replace only that part
of the system that is damaged. This results in lower replacement
costs for the patient. Another advantage is that the patient can
first buy a more "standard" respiratory system and later on upgrade
his standard respiratory system as he wants. The patient can for
instance add a humidifier system, a controller, a human machine
interface or any other part to the standard respiratory system.
Another advantage is that the modular design allows manufacturing
different parts on different locations and/or in different
countries and/or by different companies.
[0104] The gas conducting system of the respiratory system
according to the eighth aspect of the invention may comprise a
conduit of one single length. Alternatively, the conduit may be
formed by a number of shorter length interconnecting conduit
sections which are removably connectable to each other.
[0105] These interconnecting conduit sections have the advantage
that it is possible to extend the existing conduit if required.
Using for instance interconnecting conduits of 0.6 m single length,
the user can for example make a piece of conduit of 1.8 m from 3
pieces of interconnecting conduit sections.
[0106] Another advantage of these interconnecting conduit sections
is that not the whole conduit has to be replaced in case of damage
to the conduit. It is sufficient to replace only the individual
damaged interconnecting conduit. These interconnecting conduits
allow thus to reduce replacement costs.
[0107] Preferably, the respiratory system according to the eighth
aspect of the invention further comprises a humidifier system for
heating and humidifying the breathable gas to be supplied to the
patient which is removably connectable between two parts of the gas
conducting system.
[0108] The connection of the humidifier system to the parts of the
gas conducting system can be done in any way considered suitable by
the person skilled in the art. The humidifier system may for
instance directly connect to a conduit section or via a cuff
according to the sixth aspect of the invention or any other
connection system. The humidifier system may be any type of
humidifier system, but preferably is a humidifier system according
to the fourth and/or fifth aspect of the invention. Preferably, in
order to further increase the performance of the humidifier system,
at least part of the humidifier system is thermally insulated from
ambient conditions. As a result, the performance of the humidifier
system can be made less dependant on the ambient conditions and is
able to perform better in challenged conditions. As such, even at
restricted power consumption, the humidifier is able to generate
more humidity compared to a humidifier without insulation.
[0109] Preferably, the respiratory system according to the eighth
aspect of the invention further comprises a cuff according to the
sixth aspect of the invention. The cuff can be used to removably
connect any parts of the respiratory system, such as for instance
the conduit to the mask, two interconnecting conduit sections, the
humidifier system to the conduit.
[0110] Preferably, the respiratory system according to the eighth
aspect of the invention further comprises a controller section for
controlling at least one respiratory care parameter of the
respiratory system.
[0111] The controller can be used to control any respiratory care
parameter. The controller can for instance provided for controlling
the heating of a hose and/or a humidifier to provide the patient
with the correct breathable gas temperature and/or with the correct
humidification levels. The controller can for instance be used to
control the temperature, humidity, gas/fluid concentrations,
gas/fluid flow rates and pressure of the medium which is passed
through the hose. The controller can also be used to control other
items of the hose systems, for instance the temperature and
humidity level inside the patient's mask. Preferably, the set up of
the controller is such that condensation inside the hose system,
i.e. inside the hose and/or the mask, is avoided. The controller
can be used to control one hose system or multiple hose
systems.
[0112] The controller can be used for controlling additional
systems, for example humidifiers, CPAP units and ventilation
systems. The controller can be used for controlling additional
heating systems, such as therapeutic blankets, heated joint pads or
bed blankets.
[0113] The controller may be any type of controller considered
suitable by the person skilled in the art. The controller may be a
controller which is integrated in the flow generator, a controller
which is integrated into a controller section forming part of the
gas conducting system or an independent controller, which is
physically not connected to the respiratory system.
[0114] A preferred embodiment of the controller is a controller
which is integrated into a controller section forming part of the
gas conducting system. An advantage of such a system is that no
communication link to another controller needs to be established,
which may result in a reduction of the number of wires of the
overall respiratory system. Preferably, the controller section
comprises a passage for the breathable gas flowing in the
respiratory system and at least one integrated sensor in the
passage for measuring respiratory care parameters of the breathable
gas. This results in a reduction of the amount of wiring needed to
connect the sensors with the controller, compared to the existing
systems where the sensors are usually provided external to the
controller. Another advantage is that such a controller is not
limited to the number of parameters that can be measured. In
existing systems the number of parameters that can be measured is
usually limited because each of the sensors need to be connected
with the controller and the amount of wiring is limited. Such a
controller further has the advantage that, if a patient requires an
upgrade of its respiratory system, it does not necessarily need to
replace its complete conduit system. It may be sufficient to
replace the controller with another controller that comprises more
or other sensors.
[0115] Such a controller is in particular suited for use in a
modular respiratory system where two or more parts are removably
connectable to each other, offering the same advantages as the
removable cuff according to a sixth aspect of the invention.
[0116] Preferably, the respiratory system according to the eighth
aspect of the invention further comprises a human machine interface
(HMI) controlling respiratory care parameters of the respiratory
system.
[0117] Preferably, the HMI is removably connectable to a part of
the respiratory system. A removable HMI has the advantage that it
is re-usable, cost-efficient and that it can be manufactured
independent of the other respiratory parts. The human machine
interface can also be fixedly connected to a part of the
respiratory system or made physically independent of the
respiratory system. An independent HMI has the advantage that it
can be placed close to the patient or remote from the patient, such
that it may be operated by another person.
[0118] Preferably, at least part of the respiratory system
according to the eighth aspect of the invention comprises a
thermochromic material. Thermochromic (TC) products change color in
response to temperature fluctuations using TC substances like
liquid crystals and leuco dyes. Today, liquid crystals are used in
many products, including aquarium thermometers, stress testers,
forehead thermometers, and other applications. While liquid crystal
TC materials are extremely capable materials, they are very
difficult to work with and require highly specialized manufacturing
techniques. The other type of TC material is called a leuco dye and
is commonly used in security printing, novelty applications such as
temperature sensitive plastics and mugs, product labels,
advertising specialties, and textiles.
[0119] The use of thermochromic materials in at least part of the
respiratory system allow to visual indicate temperature and
temperature change. It allows patients and nurses to monitor the
temperature and observe temperature change without the need for
exact readings from displays. The thermochromic material can act as
a safety mechanism in components that are heated or become warm
upon use, for instance in a hose which comprises a heating element
for heating a breathable gas. As soon as a threshold temperature is
exceeded, the patient or nurse will be triggered by the color
change.
[0120] In general, thermochromic materials can be applied in a
respiratory system to act as a communication to visualize messages
on heated respiratory parts, such as warning messages, company
brand names, logos or other visual identifications.
[0121] The thermochromic substances can be applied in a number of
different ways.
[0122] As a first example, a respiratory part may be extruded using
a thermochromic material which extends throughout the entire
respiratory part using active TC substances or formulated active TC
substances in the form of a masterbatch. Examples of extruded
respiratory parts are a conduit or part of a respiratory conduit
such as a rib of a hose or heated hose; a jacket material of cables
or insulation material of wires such as heating wires and signal
wires. The TC can be incorporated over the entire extruded part or
in a section of the extruded part. As a second example, a
respiratory part may be co-extruded using active TC substances or
formulated active TC substances in the form of a masterbatch.
Examples of co-extruded respiratory part are a respiratory conduit
or part of a conduit such as a rib of a hose or heated hose, a
jacket material of cables or insulation material of wires such as
heating wires and signal wires. The TC material can be incorporated
over the entire co-extruded part or in a section of the co-extruded
part. As a third example, use can be made of injection moulding,
low pressure injection or over-moulding using active TC substances
or formulated active TC substances in the form of a masterbatch.
Examples of injection moulded products are cuffs of hoses, in
connectors, in humidifier parts such as humidifier chambers, in
filters, Y pieces. The TC material can be moulded in the entire
part or only in a section of the moulded part. As a fourth example,
use can be made of in-mould labelling of a component treated with a
TC substance to allow cost effective application of the TC
substance. As a fifth example all kinds of surface treatments are
possible, such as for example: [0123] a) Printing: TC substances
can be printed directly on the substrate e.g. to visualize the
brand name of a company, a temperature scale, logo etc. [0124] b)
Painting: TC substance can be applied by liquid painting of a
lacquer or water based solution or dispersion [0125] c) Spraying:
TC substance can be applied by spraying powder or liquid [0126] d)
Dipping: TC substances can be applied by dipping the substrate into
a solution or dispersion of the active TC substance or any
formulation thereof. [0127] d) Gluing [0128] e) Laser marking
[0129] As a sixth example thermochromic components may be inserted
into a part of the respiratory system. A thermochromic thermometer
may for instance be inserted in the hose, cuff or respiratory mask
of the respiratory system.
[0130] Preferably, at least part of the respiratory system
according to the eighth aspect of the invention comprises an
antimicrobial (AM) material.
[0131] The use of antimicrobial materials in the respiratory system
has a number of advantages. AM materials provide additional hurdle
in the prevention of ventilator associated pneumonia, an effect
that often occurs with ventilated patients especially in hospitals
and intensive care units. AM materials also provides additional
hurdle in the prevention of cross-contamination, i.e. the patient
becoming colonized and infected by external flora or internal
flora. The incorporation of antimicrobial substances or the surface
treatment with antimicrobial substances can help reduce the
microbial counts in the respiratory system. AM property also
provides protection against material degradation and odour
formation.
[0132] The AM material can be applied to the entire respiratory
system or only to certain part of the respiratory system.
Preferably, the AM material is at least applied to those
respiratory parts that are prone to develop microbial colonization
(e.g. presence or availability of water/moisture/humidity,
increased temperature, etc). AM treated respiratory parts can
include, but are not limited to, the patient interface such as the
respiratory mask (face mask, nose mask, tension straps, pressure
cushion, etc) or the endotracheal tube, Y-pieces, the cuffs
(sensing cuffs, communication cuffs, adaptor cuffs, connection
cuffs, . . . ), the sensors or the coating on the sensors, the
hose, the heated hose, the heating and signal wires inside the hose
lumen or outside the hose, the humidifier system (e.g. humidifier
chamber), the HMI, the controller.
[0133] AM materials may include organic (e.g. triclosan, zinc
pyrithione, etc) and/or inorganic substances (silver-based
substances, copper-based substances and combinations thereof, etc)
and/or combinations thereof. AM substances can be migrating and
non-migrating compounds providing AM activity e.g. by interacting
with the cell membrane and/or by interaction with the cell
metabolism or by destructing the cellular protection mechanisms
(cell wall, cell membrane, etc). AM compounds can provide slow
release of the active substance (e.g. silver based substances,
encapsulated AM substances in matrices like zeolite or glass,
etc).
[0134] In general, it is advised to apply AM substances in the top
layer of an article in order to allow the MA substance to interact
with the environment (i.e. bacteria, fungi, yeasts, mold, mildew,
etc).
[0135] The AM material can be applied to any part of the
respiratory system in a number of different ways. As a first
example, a respiratory part may be extruded using active AM
substances or formulated active AM substances in the form of a
masterbatch. Examples of extruded respiratory parts are a conduit
or part of a respiratory conduit such as a rib of a hose or heated
hose; a jacket material of cables or insulation material of wires
such as heating wires and signal wires. The AM material can be
incorporated over the entire extruded part or in a section of the
extruded part. As a second example, a respiratory part may be
co-extruded using using active AM substances or formulated active
AM substances in the form of a masterbatch. Examples of co-extruded
respiratory part are a respiratory conduit or part of a conduit
such as a rib of a hose or heated hose, a jacket material of cables
or insulation material of wires such as heating wires and signal
wires. The AM material can be incorporated over the entire
co-extruded part or in a section of the co-extruded part. As a
third example, use can be made of injection moulding, low pressure
injection or over-moulding using active AM substances or formulated
active AM substances in the form of a masterbatch. Examples of
injection moulded products are cuffs of hoses, in connectors, in
humidifier parts such as humidifier chambers, in filters, Y pieces.
The AM material can be moulded in the entire part or only in a
section of the moulded part. As a fourth example, use can be made
of in-mould labelling of a component treated with an AM substance
to allow cost effective application of the AM substance. As a fifth
example all kinds of surface treatments are possible, such as for
example: [0136] a) Printing: AM substances can be printed directly
on the substrate [0137] b) Painting: AM substance can be applied by
liquid painting of a lacquer or water based solution or dispersion
[0138] c) Spraying: AM substance can be applied by spraying powder
or liquid [0139] d) Dipping: AM substances can be applied by
dipping the substrate into a solution or dispersion of the active
AM substance or any formulation thereof. [0140] d) Gluing [0141] e)
Laser marking [0142] f) Vacuum deposition [0143] g) chemical vapor
deposition [0144] h) Physical vapor deposition
[0145] The conduit as used in any aspect of this invention
preferably comprises a hose with at least 4 associated wires, two
of them being heating wires for the purpose of heating the
breathable gas passing within the conduit, two of them being
control wires for the purpose of transmitting signals from
measuring device, such as pressure sensors or temperature sensors.
A 4 wire circuit has a number of advantages. A first advantage is
that the heating and signal circuits do not have to work on a
switching basis, but can operate independently and monitor and heat
the conduit continuously. In fact, the signal wires are able to
monitor continuously the measurements of the at least one sensor
and that, at the same time, the heater wires are able to
continuously heat the breathable gas passing through the conduit.
As a result, such a 4 wire construction allows to respond faster to
changes in the conduit compared to switch circuits. Another
advantage of such a 4 wire construction is that, since the current
may continuously circulate through the at least one sensor, a
greater stability of the at least one sensor may be obtained and
therefore accuracy can be improved. A third advantage is that such
a 4 wire circuit does not need a complex control circuit, which
results in reduced costs.
[0146] The wires to control such a 4 wire circuit can be associated
with the hose of the conduit by any possible way considered
suitable by the person skilled in the art. The wires can for
instance been located in a hose structure, which can be helically
wound, extrusion blowmoulded or extrusion pipe. The wires can also
be located down the middle of the respiratory conduit. The wires
may also be located externally of the respiratory conduit. In
particular, such a 4 wire circuit may for instance be introduced
into a conduit obtained with the method according to a second
aspect of the invention, comprising a hose with at least one
helical wire groove, preferably with two helical wire grooves. In
particular, such a 4 wire circuit may be incorporated into a
conduit according to a third aspect of the invention, wherein for
instance the two heater wires are incorporated into a first helical
rib, and the two signal wires are incorporated into a second,
parallel extending helical rib.
[0147] The hose as used in any aspect of this invention may
comprise an inner tube, with a smaller diameter than the hose, and
being at least partly attached to an inner face of the hose and
provided for holding at least one wire. The at least one wire can
be any type of wire, such as a heater wire, signal wire,
communication wire. The tube may be a composite cable, comprising
at least one wire, being at least partly attached to an inner face
of the hose. The at least one wire may for instance be a NTC or PTC
wire. The tube or cable may be attached along the whole of its
length or at one or more selected positions. The tube may comprise
one ore more wires, for instance the tube may comprise a cable and
a signal wire. An advantage of inserting at least one wire in a
hose in the above described manner is that a large variety and
number of wires can be incorporated. This allows a wide range of
sensors to be applied in the conduit, which allow a large range of
control possibilities. Preferably, the tube is attached to the
inner surface of the hose in a straight pathway, because this
results in a reduction of the used material in comparison to the
helix route, and thus in a reduction of the material cost. Another
advantage is that it is easier to recycle the materials used to
make the conduit. If desired a strain relief can be added to the
structure. This may be a form of polymer chord which will prevent
stretching of the conduit to greater than the design allowance.
[0148] The conduit is preferably made of a thermoplastic material,
and structured to be flexible and lightweight. The production
process to produce the conduit may be any process considered
suitable by the person skilled in the art. As an example, but not
limited thereto, the following production processes are possible:
[0149] (a) Spirally wound from one or more profiles of material.
[0150] (b) Spirally wound with an inner web and outer helix. There
may be one or more helix forms along the product. [0151] (c)
Extruded tube which is reinforced to prevent kinking. [0152] (d)
Extrusion blow moulded conduit. [0153] (e) Formed from a tape or
similar with a reinforcement material.
[0154] Any technique considered suitable by the person skilled in
the art may be used to terminate the conduit used in any aspect of
the present invention.
[0155] Use may for instance be made of low pressure injection
(LPI). This technique can be used to terminate the conduit with the
required sensors, contact connectors and cuffs to link to other
parts of the system. The components would generally be injection
moulded parts of compatible plastic materials. The sequence of
steps will vary with the number of elements required in the
termination. An example would be to add to the conduit a cuff to
act as a linking device and a platform for terminals etc. In such a
case the component and conduit are placed in a moulding tool. The
LPI material is introduced to the desired position to bond the cuff
to the conduit. The material can be introduced by low pressure
injection or by intrusion moulding machines. The required terminals
etc can then be added to the cuff and the assembly completed. In
another form the terminal cuff assembly may be completed and then
added to the conduit by the LPI process. Such processes are in use
by Plastiflex to terminate electrical hose systems for the
floorcare market. The process can be used to fill the space within
the terminal component to give added security and stability to the
connections within. The number of steps will be determined by the
degree of complexity of the terminal cuff and the number of
functions it is associated with. The process allows the opportunity
to use parts of a more complex shape if needed and produced to high
tolerance. A wider variety of materials may be chosen. The process
is very controlled and gives a lower assembly cost.
[0156] An alternative process to terminate the conduit is
overmoulding. The end of the conduit is directly overmoulded with a
plastic material to bond them, giving a leak free pathway for the
fluids to pass along. It also can act as the base or platform to
mount the connectors or terminals for the control system. In a next
step, the connections for the system can be made. An outer covering
which may be an injection moulded component can then be located
over the assembly and using the overmould process locked into
position onto the conduit terminal assembly. If desired this could
be further overmoulded to add other features for example "soft
touch". A stress relief feature can be a part of the overmould
design. Alternatively the stress relief feature can be a separate
moulded part, placed on the conduit and locked to position as a
part of the overmould process. The terminal cuff can be designed to
allow a range of fittings or contacts to be made in the same
structure. This can be used to produce a variety of complexity and
control from the same base part. This has a cost benefit to all
such variations of the cuff.
DESCRIPTION OF THE DRAWINGS
[0157] The present invention will be described with respect to
particular embodiments and with reference to certain drawings but
the invention is not limited thereto but only by the claims. The
drawings described are only schematic and are non-limiting. In the
drawings, the size of some of the elements may be exaggerated and
not drawn on scale for illustrative purposes. The dimensions and
the relative dimensions do not necessarily correspond to actual
reductions to practice of the invention.
[0158] Furthermore, the terms first, second, third and the like in
the description and in the claims, are used for distinguishing
between similar elements and not necessarily for describing a
sequential or chronological order. The terms are interchangeable
under appropriate circumstances and the embodiments of the
invention can operate in other sequences than described or
illustrated herein.
[0159] Moreover, the terms top, bottom, over, under and the like in
the description and the claims are used for descriptive purposes
and not necessarily for describing relative positions. The terms so
used are interchangeable under appropriate circumstances and the
embodiments of the invention described herein can operate in other
orientations than described or illustrated herein.
[0160] The term "comprising", used in the claims, should not be
interpreted as being restricted to the means listed thereafter; it
does not exclude other elements or steps. Thus, the scope of the
expression "a device comprising means A and B" should not be
limited to devices consisting only of components A and B. It means
that with respect to the present invention, the only relevant
components of the device are A and B.
[0161] The invention will be further elucidated by means of the
following description and the appended figures.
[0162] FIG. 1 shows a first preferred embodiment of a heating
element 37 of a conduit according to an aspect of the invention.
The heating element 37 is a coaxial cable construction, which
comprises two electrical wires 20, 21, one of which being a heating
wire 21, the two electrical wires 20, 21 being separated by a
negative temperature coefficient component layer 22. In particular,
FIG. 1 shows a coaxial cable construction comprising a heating wire
21 which is helically wound around a textile core 35, a NTC doped
polymer coating 22 surrounding the heating wire 21 and a signal
wire 20 which is helically wound around the NTC coating 22. The
signal wire 20 can be insulated or not. Preferably, an insulation
layer 23 is applied around the aforementioned construction as is
shown in FIG. 1.
[0163] After association of the heating element 37 with a hose, the
coaxial wire will allow heating and controlling of the breathable
gas flowing through the hose. The coaxial wire heating element 37
as shown in FIG. 1 will use the reduced resistance of the NTC
component layer 22 at rising temperature to trigger the power
supply to the heating wire. This allows the heating element 37 to
detect and minimize overheating inside the hose. As such, the
heating element 37 will also allow detecting and minimizing hot
spot sections of the heating wire 21. The heating element 37 of the
conduit shown in FIG. 1 preferably has the following further
properties/advantages: low power/wattage, thermostatic control,
UL/CSA certified, low cost option, smallest overall diameter,
105.degree. C. continuous rated PVC, hot spot detection, overall
temperature monitoring.
[0164] FIG. 2 shows a second preferred embodiment of the heating
element 37 provided in the conduit according to an aspect of the
invention.
[0165] The heating element 37 is a coaxial cable construction. The
construction comprises two heating wires 21 in the core of the
construction which extend in longitudinal direction of the hose.
Each of the heating wires 21 has a ceramic coating for insulation.
The heating wires 21 are electrically connected to each other at
one end, and at the other end they are connected to the same power
supply. A NTC coating layer 22 surrounds the heating wires 21. A
signal wire 20 is applied around the coating layer 22. In FIG. 2,
the signal wire 20 is helically wound around the coating layer, but
it may be applied in any other way considered suitable by the
person skilled in the art. The signal wire 20 can be insulated or
not. Preferably, an insulation layer 23 is applied around the
aforementioned construction as is shown in FIG. 2. The outer
insulation layer allows the coaxial wire heating element 37 to be
in direct contact with the breathable gas within the hose without
causing short circuit.
[0166] In addition to the advantages of the heating element shown
in FIG. 1, the heating element shown in FIG. 2 has the advantage
that only one cable has to be incorporated into the hose for
heating the breathable gas within the conduit. In general, in order
to provide a closed electrical circuit, there are two wires in the
conduit, one wire going to the patient interface and one going back
to the flow generator. The co-axial cable configuration shown in
FIG. 2 offers a more compact heating element, in which the two
wires are incorporated into one single cable which can be
incorporated as a single cable into the hose.
[0167] Optionally, the heating elements 37 shown in FIGS. 1 and 2
may comprise a PTC coating layer instead of a NTC coating layer.
The cross section of a heating cable, such as for instance the
coaxial cable construction as shown in FIGS. 1 and 2, can have any
shape considered suitable by the person skilled in the art, such as
round or oval. Preferably, a heating cable has an elliptical
diameter as is shown in FIG. 3. Such an aerodynamic wire structure
offers a number of different advantages. It improves breathing
pressure drop, minimizes air turbulence, minimizes moisture buildup
and reduces bacterial build up. It allows a spring wounded heating
cable to be torqued against the hoses inner wall. It further allows
improved heat dispersion into the wall of the hose through a
greater contact area. It further improves aerodynamics with a
profiled shape and location against the hose wall. The elliptical
shape further allows the formation of rod into spring
characteristics.
[0168] Cable constructions, as for instance coaxial cable
constructions as shown in FIGS. 1 and 2 allow for an easy and
compact insertion of the heating element into the hose. The
insertion can be done by any method considered suitable by the
person skilled in the art. The coaxial cable construction can for
instance be inserted into an internal or external wall, into an
internal or external rib of the hose, into an internal or external
groove of the wall, loosely provided within the hose, would like a
spring.
[0169] FIG. 3 shows a coaxial wire heating element 37 which is
wound like a spring and removably inserted into a hose 36. The
wounding of the coaxial wire heating element 37 as a spring and the
insertion into the hose 36 can be done in any way considered
suitable by the person skilled in the art. To insert the coaxial
wire heating element 37 into the hose 36, the wire 37 is for
instance connected to a spider rod and is inserted in the hose 36
by using a heavy bullet or ball or weight device in any form. The
diameter or thickness of the bullet or weight is smaller than the
internal diameter of the conduit. The bullet is connected to a
locater wire and dropped into the hose at one end. By falling
through the hose using gravity, the locator wire is pulled through
leaving the spider rod exposed at the other end of the hose. The
spider rod is then assembled with a spider and with the coaxial
wire heating system. The spider rod and heating element 37 are then
pulled into the correct position. At that moment, the heating
element 37 is assembled in the conduit. Applying a slight tortional
force, the wire 37 behaving as a spring, is brought into position,
making contact with the conduit inner wall. The wire is then locked
into position using the spider keeping one end of the spring wire
in position. The spider rod is then disengaged from the location
spider by rotating the spider rod to disengage location pegs. The
heating wire 37 is then assembled in the conduit. This technique
can be used to insert any type of wire into the conduit, for
instance a heater wire, signal wire, combined cable
construction.
[0170] The construction shown in FIG. 3 has the advantage that the
heating element 37 is removably inserted into the hose. The heating
element 37 can thus be re-used and does not have to be thrown away
together with the hose, which leads to lower replacement costs.
This is in particular of importance for hoses which have to be
periodically replaced, such as for example heated respiratory
hoses. Other advantages of the construction shown in FIG. 3 are
that it contributes to improved conductivity between the coaxial
wire heated element 37 and the hose wall and that it improves heat
dispersion within the hose and energy use of the heating element.
The heating element as shown in FIG. 3 may comprise a NTC or a PTC
component.
[0171] FIG. 4 shows a conduit which is manufactured according to an
aspect of the invention. The conduit comprises a blowmoulded tube
38 which comprises a corrugated wall 39. The corrugated wall 39 of
the tube 38 comprises a number of corrugations. The tube 38 further
comprises a helical wire groove 40 on the exterior surface of the
tube. A wire for heating or communication purposes is inserted in
the wire groove 40. When a heating wire is for instance inserted in
the wire groove 40, this configuration contributes to improved
conductivity between the heating wire and the tube wall 39 and it
improves heat dispersion within the tube and energy use of the
heating wire. Because these helical wire grooves 40 can be created
directly from the extrusion machines, this construction offers a
fast and cost-efficient solution to insert heating wires in a hose.
Moreover, this construction has the advantage that the helical wire
groove 40 can be provided at whatever possible pitch. Preferably,
the pitch of the helical wire groove 40 is larger than the hose
pitch of the corrugations 39 of the hose itself, such that less
heater wire is needed to provide the same length of the hose. This
results in a reduction of costs of the heated conduit.
[0172] FIG. 5 shows a conduit for use in a respiratory system for
supplying a breathable gas from a flow generator to a patient
interface. The conduit shown in FIG. 5 comprises a double pitch
hose 50, which comprises two parallel extending helical ribs 16, 17
at an outer surface of the hose 50. In FIG. 5 only one of the ribs
comprises a wire. Alternatively, both ribs may comprise one or more
wires. This wire may be a heater wire, a communication wire, or a
combined cable construction as shown in FIGS. 1 and 2 or any other
wire or cable. Conduits like the one of FIG. 5 can be made by a
blowmoulding process or a helical winding process.
[0173] FIG. 6 shows a first preferred embodiment of the respiratory
system according to a fourth aspect of the invention. The
respiratory system comprises a flow generator 12, a humidifier
system 41 for heating and humidifying a breathable gas received
from the flow generator 12 and a conduit 54 for supplying a
breathable gas from the humidifier system 41 to a patient interface
43. The humidifier system 41 comprises an inlet for taking in a
breathable gas and a humidification chamber 53 connected to the
inlet and provided for heating and humidifying the breathable gas
before delivery to the conduit 54. The flow generator 12 is
connected with the inlet of the humidification chamber 53 through a
heated inlet hose 52, which functions as a pre-conditioning system.
An inlet heating element is associated with the inlet hose 52 and
pre-heats the breathable air before entry into the humidification
chamber 53. The flow generator 12 may also be a CPAP unit with an
integrated humidifier and heating system, which is here used as the
pre-conditioning system. The amount of heating is under control of
a controller and may be determined based on a measurement of
ambient air characteristics or characteristics of the breathable
gas in the inlet, for instance a dewpoint measurement.
[0174] FIG. 7 shows a second preferred embodiment of the
respiratory system according to a fourth aspect of the invention.
The respiratory system comprises a flow generator 12 with an
integrated humidifier system 55 for heating and humidifying a
breathable gas and a conduit for supplying a breathable gas from
the humidifier system 55 to a patient interface 43. The respiratory
system comprises a pre-conditioning system for pre-conditioning the
breathable gas before entry into the flow generator. This
pre-conditioning system is here integrated into the CPAP unit and
may comprise a temperature control system for influencing the
temperature of the breathable gas or a humidity control system for
influencing the humidity of the breathable gas before entry into
the flow generator and the subsequent main humidifier of the
system. The amount of heating is under control of a controller and
may be determined based on a measurement of ambient air
characteristics or characteristics of the breathable gas.
Optionally, the flow generator 12 with the integrated humidifier
system and preconditioning system 55 can be used itself as a
pre-conditioning system for heating and humidifying the breathable
gas before entry into a second humidifier system (not shown).
[0175] In the respiratory systems of FIGS. 6 and 7 also a fifth
aspect of the invention is applied, namely to control of the
temperature and humidity levels of the air traveling from the
humidifier chamber to the patient on the basis of a dewpoint
measurement in this part of the conduit 54, preferably at least at
the patient interface.
[0176] Preferably, in order to further optimize the efficiency of
the humidifier system of the respiratory system, the temperature of
the water in the reservoir of the humidification chamber is set
sufficiently high to generate enough heat capacity of the water
enabling efficient energy transfer to moisturize the air flow and
to heat up the air flow (if necessary). The temperature of the
water in the reservoir of the humidification chamber is preferably
controlled. The control can for instance be done based on the
ambient air conditions or based on dewpoint measurement of the
breathable gas.
[0177] Optionally, in order to further optimize moisture and heat
transfer to the breathable gas, the construction of the reservoir
and humidification chamber of the humidifier system may be as
follows: [0178] Reservoir and humidification chamber enabling
longer residence time of the transported air using baffles [0179]
Reservoir and humidification chamber having headspace volume more
than 100 ml [0180] Reservoir and humidification chamber with air
inlet that creates turbulence to maximize contact surface between
air and water [0181] Reservoir and humidification chamber that can
be heated to temperatures between 5.degree. C. and 100.degree. C.
[0182] Humidifier system has overheating control [0183] Humidifier
system allows maximizing the humidity transfer into the outlet air
flow [0184] Humidifier system allows the inlet air to percolate
through the water in the reservoir [0185] Humidifier system uses
ultrasonic systems to generate vapor droplets.
[0186] Preferably, in order to further increase the performance of
a humidifier system, the water reservoir of the humidifier system
is thermally insulated. As a result, the performance of the
humidifier system can be made less dependant on the ambient
conditions and is able to perform better in challenged conditions.
As such, even at restricted power consumption, the humidifier is
able to generate more humidity compared to a humidifier without
insulated tank, as can be seen from table 1. In table 1,
T.sub.waterbath is the temperature of the water in the
humidification chamber, Td.sub.ambient is the ambient air
temperature and Td.sub.output is the dewpoint temperature of the
breathable air leaving the humidification chamber, which is a
measure for humidity level of the breathable air.
TABLE-US-00001 Tank T.sub.waterbath Td.sub.ambient Td.sub.output
Without insulation 55.degree. C. 17.degree. C. 21.0.degree. C. With
insulation 69.degree. C. 17.degree. C. 24.5.degree. C.
[0187] In case the humidifier system is integrated in a flow
generator, the power consumption of the total system might be
restricted. An insulated humidifier chamber will help to save
energy and effective use of power to maximize the humidity output
of the system.
[0188] The insulation of the humidifier system can be done with any
means considered suitable by the person skilled in the art. The
humidification chamber may be for instance a double walled chamber
construction. The cavity between the two wall can either be vacuum,
air or filled with an insulating material, for instance with foam.
A double walled chamber construction in which the cavity is air
filled and allows the air coming from the flow generator to pass
through prior to passing over the headspace of the water surface is
preferred. The humidification chamber may comprise an insulation
layer in the form of a material attached, glued, connected to the
water chamber. The insulation material can be a foamed material, a
textile construction.
[0189] Test results disclosed hereunder prove that neither of the
tested systems, when operated under normal conditions and
challenged conditions are able to deliver the optimal setting for
humidity and temperature but stay well below this optimal setting
especially for absolute humidity. The test results prove that the
efficiency of a humidifier in delivering warm and moisturized
breathable gas to a patient can be significantly improved with a
respiratory system according to a fourth and/or fifth aspect of the
invention.
Test Results
[0190] 1. Benchmark testing:
[0191] F&P HC 604: CPAP with integrated heated humidifier and
Thermosmart.RTM. technology.
Settings:
[0192] Pressure: 10 cm H2O
[0193] Variable parameter: heating of the heated hose from 0 (Off)
to 10
Results and discussion
[0194] The F&P machine was tested in different ambient
conditions.
[0195] Tw=temperature of water in reservoir (.degree. C.)
[0196] T=temperature of outlet air (.degree. C.) measured with
Hanna-Instruments Thermo-hygrometer HI9565
[0197] Td=dewpoint of outlet air (.degree. C.) measured with
Hanna-Instruments Thermo-hygrometer HI 9565
TABLE-US-00002 1 2 3 T ambient = T ambient = T ambient =
13-14.degree. C. 21.degree. C. 22-23.degree. C. Setting Td ambient
= Td ambient = Td ambient = Heated 9-9.5.degree. C. 9-9.5.degree.
C. 9-9.5.degree. C. Hose T w T Td Tw T Td Tw T Td 0 53-54 19.8 19.5
53 25 21.1 57-58 27.4 20.7 5 53-54 21 20 55 25.8 21.8 10 53-54 23.1
20 56 27.5 21.8 58 30.7 21.1
Column 1:
[0198] At an ambient temperature of 13-14.degree. C., the HH
generated an airflow with a dewpoint of 19.5.degree. C. (eq. to
16,8 mg water/l air). At these extreme conditions, condensation was
visible in the unheated hose. Ref. condensation appears when the
temperature of the outlet air equals the dewpoint of the outlet
air.
[0199] When the T-setting on the heated hose was increased, the
temperature of the outlet air significantly increased from
19,8.degree. C. to 23.degree. C.
[0200] This temperature increase was able to remove the condensate
(T outlet air>T dewpoint). The temperature of the outlet air did
not reach 30.degree. C.
[0201] The temperature increase due to heating the hose did not
have an impact on the dewpoint of the outlet air. This is logical
since the dewpoint of the outlet air is determined by the
efficiency of the HH.
Columns 2 and 3:
[0202] The same effects were observed in the experiments summarized
in columns 2 and 3. By activating the hose heating system, the
temperature of the outlet air is significantly increased. The
dewpoint of the outlet air is unaffected (note in column 2: the
slight increase in dewpoint is due to the increase in the
temperature of the waterbath of the HH).
Conclusion
[0203] The heated hose of the F&P machine significantly
increases the temperature of the outlet air. At ambient conditions
around 22-23.degree. C., the outlet air temperature can reach the
desired 30.degree. C. [0204] The heated hose of the F&P machine
is able to avoid condensation, even at extreme conditions of
ambient temperatures around 13-14.degree. C. Under these
conditions, an outlet air temperature of 30.degree. C. was not
achieved. It is yet not clear whether the system will be able to
avoid condensation at ambient temperatures of 5.degree. C. (as
mentioned in the technical specifications). [0205] From these
experiments, it seems that the F&P HH with heated hose is not
able to deliver the 30 mg water/liter of air (equivalent to a
dewpoint of around 30.degree. C.), neither in comfortable ambient
conditions of 21-23.degree. C., neither in challenged conditions
(13-14.degree. C.).
[0206] The maximum dewpoint was around 21-22.degree. C. or
equivalent to 18,3-19,3 mg water/liter air).
2. Test setup according to the invention
[0207] The experimental setup comprises:
[0208] A Breas i-Sleep 10 CPAP unit connected with a Breas Heated
Humidifier HA 50 via a CPAP inlet hose of 1,8 meter with heating
element.
[0209] A CPAP outlet hose of 1,8 meter with heating element.
[0210] Settings of the CPAP unit:
[0211] Pressure: 10 cm H.sub.2O
[0212] Settings of the HH:
[0213] Heating from 0 to 9
Experiment 1:
[0214] Air flow: 10
TABLE-US-00003 Heating Heatting T ambient = 13-14.degree. C.
Setting Inlet Outlet Other Td ambient = 9-9.5.degree. C. HH Hose
hose mofifications T w T Td 1 9 off on 45 25.4 18.3 2 9 on on 45
25.9 21.4 3 9 on on with plug in 45 28.3 24.4 4 5 on on with plug
in 38.6 27.1 21.6
Line 1-Line 2: Effect of Heating the Inlet Air:
[0215] When the inlet air was not heated, the dewpoint of the
outlet air is 18,3.degree. C. (equivalent to 15.6 mg water/liter
air). With the heating system in the inlet hose on, the dewpoint is
increased to 21,4.degree. C. or 18.7 mg/l. This is an increase of
20% in vapor content. Note that heating the inlet air does not have
a significant effect on the outlet air temperature.
Line 2-Line 3: Effect of Air Turbulence on Water Surface
[0216] A plug was mounted on the inlet on the inside of the HH in
order to create turbulence on the water surface in the reservoir.
The plug is also expected to have an effect on the air flow speed
(air flow reduction).
[0217] As a result of mounting the plug, another 3.degree. C.
dewpoint increase was noticed. There also seemed to be a better
heat transfer from the hot water in the reservoir to the air flow
(T outlet air also increased with>2.degree. C.). Under the same
conditions, a sufficiently higher dewpoint was reached compared to
the F&P machine.
Line 3-Line 4: Effect of Water Bath Temperature
[0218] Decreasing the water bath temperature from 45.degree. C. to
38-39.degree. C. resulted in a drop in dewpoint of 3.degree. C.
indicating that the water has a reduced heat capacity. Energy in
transferred in heating the outlet air and moisturizing the air
flow. By reducing the water bath temperature, moisturizing the
outlet air is less efficient. The effect on the outlet air
temperature is minimized due to the heating of the outlet air in
the outlet hose.
Conclusion:
[0219] By introducing heated air into the HH (e.g. via a heating
element in the inlet hose), the capacity of the inlet air to hold
moisture is significantly increased. By heating up the cold air,
energy extraction for heating up the air flow from the water bath
is minimized so more energy is available for vaporization. The
result is a better efficiency of the HH. [0220] By creating
turbulence on the water surface and increasing the residence time
in the HH (by slowing down air flow), more humidity and heat is
transferred to the outlet air flow resulting in a higher dewpoint
and outlet air temperature. [0221] By increasing the temperature of
the HH, the heat capacity increases enabling more efficient
humidification of the outlet air.
Experiment 2
[0222] Air flow: 10
TABLE-US-00004 Heating Heatting T ambient = 13-14.degree. C.
Setting Inlet Outlet Other Td ambient = 9-9.5.degree. C. HH Hose
hose mofifications Tw T Td 9 on on 48 34.7 22.2 9 on on with
baffles 48 35.8 25.2 9 on on with plug + baffles 48 36.5 31.3
[0223] Confirmation of effect of increased residence time and water
surface turbulence:
[0224] Two baffles were introduced in the HH to force the air to
circulate over the heated water surface: increase in dewpoint of
3.degree. C. Adding the plug (restricted air flow+turbulence on
water surface) resulted in another 6.degree. C. increase in
dewpoint.
Experiment 3
[0225] Air flow: 10
TABLE-US-00005 Heating Heatting T ambient = 23.degree. C. Setting
Inlet Outlet Other Td ambient = 9-10.degree. C. HH Hose hose
mofifications Tw T Td 9 off off with baffles 48 29.3 22 9 on off
with baffles 48 29.2 23 9 on on with baffles 48 36.2 22.9
[0226] Confirmation of effect of heated inlet air: dewpoint
increase of 1.degree. C. This increase is significant but less
explicit when compared to more extreme ambient temperature of
13-14.degree. C. Very obvious effect of heating the outlet air in
the outlet hose: temperature increased with 7.degree. C.
Experiment 4
[0227] Air flow: 10
TABLE-US-00006 Heating Heatting T ambient = 22-23.degree. C.
Setting Inlet Outlet Other Td ambient = 9-9.5.degree. C. HH Hose
hose mofifications Tw T Td 9 off on 46 32.2 20.4 9 on off 46 27.4
22.5
[0228] Confirmation of effect of heating the inlet air: significant
dewpoint increase.
[0229] Turning heating of outlet air off results in significant
decrease of outlet air temperature.
Experiment 5
[0230] Air flow: 20
TABLE-US-00007 Heating Heatting T ambient = 20.degree. C. Setting
Inlet Outlet Other Td ambient = 12.degree. C. HH Hose hose
mofifications Tw T Td 1 9 on on with baffles 48 29.5 20.5 2 9 on on
with baffles 54 30.3 23.6
[0231] Confirmation of the effect of increased water bath
temperature: water bath temperature increase results in higher heat
capacity of the water and hence in a higher dewpoint and
temperature of the outlet air.
[0232] FIGS. 8 and 9 respectively show a front and rear view of the
cuff 9 according to a sixth aspect of the invention. The cuff 9
comprises a passage for a breathable gas flowing in the respiratory
system. The cuff shown in FIGS. 8 and 9 comprises an integrated
sensor 4 for measuring respiratory care parameters of the
breathable gas. The integrated sensor 4 is located in the passage
of the cuff 9. The sensor 4 is connected to electrical pins 3 via
internal wiring. The cuff 9 shown in FIGS. 8 and 9 can be connected
directly onto a part of the respiratory system or can be connected
to a connection cuff of any part of the respiratory system, for
instance with the aid of a cuff fitting 6. FIG. 9 shows for
instance an electrical male housing 2 for fitting into a female
conduit cuff. Electrical pins 3 are located within the electrical
male housing 2. As such, the electrical pins 3 of the cuff 9, may
connect directly to the internal wiring of for instance the hose,
or may connect to corresponding electrical pins of a connection
cuff of the hose. The cuff 9 as shown in FIGS. 8 and 9 comprises a
cuff housing 1a which is designed to fit the standard ISO tapper
fitting. Shown on the side of the cuff are grip features 2b to
assist the user when connecting or disconnecting the cuff via
securing clips 2a.
[0233] FIGS. 8 and 9 further show the overmould 1, which secures
internally the sensor and electrical connecting pins.
[0234] The cuff 9 may comprise multiple sensors 4. The sensors 4
may be provided for measuring any respiratory care parameters of
the breathable gas, such as temperature, humidity, pressure,
stress, strain, oxygen concentration, CO2 concentration, air flow
speed and any other parameters considered suitable by the person
skilled in the art.
[0235] The cuff 9 may comprise other modules, such as communication
modules which make use of radio frequency, bluetooth, infa-red,
microwave, fibre optics or any other like technologies. The sensors
and modules can communicate with their appropriate devices such as
individual controllers for heating, flow generators, humidifiers or
any other associated equipment for communication.
[0236] The cuff 9 can transfer information via hard wiring located
within the structure of the respiratory conduit. The wiring for the
heating and/or information transfer can be located within the
respiratory conduit or externally of the respiratory conduit.
Preferably, the wiring is located inside of the respiratory system.
This has the advantage that the user cannot tangle the wiring and
cause damage to the wiring or sensors.
[0237] The cuff connection is preferably designed for connecting
directly onto the respiratory conduit. Preferably, the cuff 9
comprises a securing system 2a to prevent the cuff 9 from
accidentally disengaging from the respiratory conduit. The signal
transfer of the at least one sensor 4 may be done by electrical
harness pins 3 engaging male and female connectors respectively
located on the parts of the respiratory system and cuff 9. This
reduces the risk to incorrect installation of the wiring or sensors
within the conduit.
[0238] The cuff 9 can be used to act as a through conduit where
additional respiratory conduits can be attached to. Additional
sensors may be externally added to the cuff 9 and connected to the
cuff 9. The additional sensors may then utilise the wiring
connected to the cuff 9.
[0239] A respiratory system can comprise more than one cuff, for
instance one at the entry of a conduit and one at the end of a
conduit to measure differences between input and output.
[0240] Sensors within the cuff 9 can be made form a variety of
materials. The need for different materials can be for system
response times, durability, sterilization and accuracy. An example
of this can be in a hospital environment where patient response and
accuracy of measurement maybe clinically more critical than in a
home therapy environment. Sterilization in hospitals places higher
demands than those in the home environment, and the sensor and
housing and connectors must with stand autoclaving.
[0241] Preferably, the cuff 9 is adapted for being fitted to hoses
of multiple sizes. This means for example that the user can utilize
smaller bore hose's closer to the patient, and this pressure drop
down the smaller hose section can be balanced by utilizing larger
bore conduit near the flow generator/humidifier.
[0242] The cuff 9 can be manufactured using a number of different
techniques, including overmoulding, intrusion moulding and or
injection moulding. The overmoulding technique can be used the
provided different material configurations for example the bore of
the cuff can be made for a harder material allowing easier
connection to associated equipment. The outer overmould 1 can be
made from a soft touch material to enable easier handling by the
patient. Sensors 4 used in the construction for the purpose of the
temperature measurement, can be any type of sensors considered
suitable by the person skilled in the art, such as NTC or PTC
components.
[0243] FIG. 10 shows a first preferred embodiment of the
respiratory mask 44 according to an aspect of the invention. The
respiratory mask comprises a heating system 45 provided for heating
the breathable gas inside the mask. The heating system 45 comprises
a heater mesh attached to the outside of the mask. Any other type
of heating system may be used and any other location of the heating
system on the mask is possible. The heater mesh is connected with
connector wires 46 to a controller for controlling, which controls
the heater mesh. The respiratory mask 44 shown in FIG. 10 has a
single wall, but may comprise a double wall, which may further
reduce the occurrence of condensation inside the mask.
[0244] FIGS. 11a and 11b show a second preferred embodiment of the
respiratory mask 44 according to an aspect of the invention. The
respiratory mask comprises a double wall formed by an outer shell
48 and an inner shell 47. The outer and inner shell enclose a
sealed cavity 49.
[0245] FIG. 12 shows a preferred embodiment of a controller 11 for
use in a modular respiratory system. The controller comprises a
cable 15 to be connected to a power supply. The controller
comprises a passage for a breathable gas flowing in the respiratory
system and at least one integrated sensor in the passage for
measuring respiratory care parameters of the breathable gas. The at
least one sensor is connected to electrical pins 10 via internal
wiring. The controller comprises a click-on part by which it is
removably connectable to a part of the respiratory system.
[0246] The controller 11 is an electronic device which is designed
in such a way that it can be powered by any number of power sources
and can be adapted to work with all common power supplies by means
of an appropriate transformer, e.g. a transformer which can be
switched according to the mains voltage of the power network where
the controller is used. If required, the controller 11 can for
instance also be powered by means of a battery.
[0247] The controller 11 is preferably provided with a user
interface 5 which allows adjusting any settings as required by the
patient, such as temperature and/or humidity of the gas delivered
to the mask. The user can adjust the settings either by hard wiring
communication or via wireless technology. The controller 11 can be
provided for collecting patient or monitoring information that can
be continuously downloaded as stream data relating to patient
comfort, sensor measurements, patient usage, technical diagnosis
and patient personal data. This information can, if required, be
stored in the controller 11 and can be downloaded at any
appropriate time. The controller can have the facility to inform
the user of relevant alarms as desired.
[0248] The controller 11 can be provided for reading information
from associated sensors of the hose system required for patient
care. Such sensors could for instance be used to measure
temperature, pressure, time, flow rates, gas mixture levels,
ambient temperatures and/or the dewpoint of the air in the hose
system. The controller 11 can for example use ambient tracking,
such as the ambient temperature, to control fluid temperature. The
controller 11 can communicate with sensors via means of hard
wiring, fibre optics, polymer resistance changes, a mechanical
interface or any other means known to the person skilled in the
art. The controller 11 can be a local controller, i.e. a controller
which is close to the hose system, or a remote controller, i.e. a
controller which is placed on a distance from the hose system.
[0249] The controller 11 is preferably designed in such a way that
it can connect to any part of the respiratory system. The
controller can be connected to one hose or to multiple hoses. These
hoses can connect to the entrance and exit of the controller, and
can then be connected to the exit of the humidifier and the patient
mask as required. The controller 11 can be connected directly to
the humidifier 41/flow generator 12 exit, after which a respiratory
conduit transfers the gas flow to the patient. The controller 11
can control the humidity levels and temperature levels for the
patient. This can be done by a number of means. Firstly the
controller 11 can measure the exit temperature and humidity levels.
This will allow the controller 11 to control the temperature to
allow the gas to maintain a 100% humidity level. The controller 11
can control the patient temperature. It is possible for the patient
to control their temperature via the controller key pad or via a
human machine interface. The controller 11 can be linked into the
humidifier and this provides the added benefit of supplying the
patient with ideal conditions. If the controller 11 is linked into
the humidifier 41 the patient can control the humidity levels and
temperature levels in combination.
[0250] The controller 11 may comprise multiple sensors. The sensors
may be provided for measuring any respiratory care parameters of
the breathable gas, such as temperature, humidity, pressure,
stress, strain, oxygen concentration, CO2 concentration, air flow
speed and any other parameters considered suitable by the person
skilled in the art. The controller 11 may comprise other modules,
such as communication modules which make use of radio frequency,
blue tooth, infa-red, microwave, fibre optics or any other like
technologies.
[0251] The controller 11 can utilise wireless technology to
communicate with other sensors/units. This technology can include
radio, Bluetooth, infrared etc.
[0252] The controller 11 can determine alarm conditions. These
conditions could include incorrect installation of the respiratory
conduit. It could include hot spot detection in cooperation with
additional technologies such as NTC/PTC wiring. The controller 11
could determine if the hose has been blocked. This is done by
measuring a number of parameters such as input and exit
temperatures, air flow etc.
[0253] FIG. 13 shows the preferred embodment of the controller 11
of FIG. 12 applied in a modular respiratory system. In FIG. 13 the
controller 11 is directly connected with one end to the flow
generator. FIG. 13 further shows the controller being connected
with another end to a conduit cuff 9, which is connected to a
conduit, the conduit being connected to a cuff 6 with the aid of a
connection cuff 7, the cuff 6 being connected to a human machine
interface 5.
[0254] FIG. 14 shows two interconnecting conduits 8 being removably
connectable to each other. Each of the interconnecting conduits 8
comprises a male fitting 7 which is removably connectable to a
female fitting 9 of another interconnecting conduit. The
interconnecting conduits 8 may contain electrical wires, provided
for heating or communication purposes.
[0255] The interconnecting conduit sections 8 may contain male and
female fittings at either end, provided to allow electrical
connection to additional conduits. The male and female fittings can
connect to controllers 11 used for the purpose of controlling, to
flow generators 12, humidifiers 41 and any other associated
equipment. The male and female fittings are designed to eliminate
the risk of incorrect installation. The fittings can be designed in
such a way as to allow swivel connections similar to those used in
the vacuum cleaner industry. The fittings of the interconnecting
conduit can connect to cuffs. This has the advantage of isolating
the cuff from the hose structure. It is normally the case that
damage occurs to the hose and not to the fitting. Manufacturers
have tried to reduce the risk of damage by introducing strain
relief, but inevitably damage does occur to the hose. Using the
interconnecting conduit sections 8 means that the user does not
need to replace the system as a whole and only needs to replace the
damaged section.
[0256] Using the interconnecting conduit sections 8 means that the
conduit system as a whole can contain different conduit
constructions as required.
[0257] For example the first section can be made from the cheaper
blowmoulding type construction, and nearer the patient a spiral
section can be used. This has the sole purpose of giving the user
the hose characteristics where they need them. Larger bore conduits
can for example be used near the flow generator/humidifier and
smaller bore hoses can be used closer to the patient. Using smaller
bore lighter weight and more flexible conduits near the patient end
will improve patient comfort. In conjunction with the conduit
sections the pressure losses down the complete system can be
balanced to minimise pressure losses. The sections can contain
valves at intermediary points along the conduit construction. These
valves for instance have the purpose of isolating backpressure and
reducing the risk of infection travelling back down the
conduit.
[0258] The interconnection conduits wiring for the
heating/information transfer can be located within the hose
structure, and this hose structure can be helically wound,
extrusion blowmoulded or extrusion pipe. The wires can also be
located down the middle of the respiratory conduit. The wires may
be located externally of the respiratory conduit.
[0259] The interconnecting conduit sections 8 can connect directly
onto the respiratory mask and can connect directly onto the
humidifier/flow generator as required. Using the standard male
female cuffs at each end of the conduits allows different hose
constructions to be used with standard cuffs. It allows the user to
select a variety of hoses for different purposes to be used. It
allows the user to have different heating configuration over the
hose length.
[0260] FIG. 15 shows a human machine interface 5 provided to
control respiratory care parameters. The human machine interface 5
shown in FIG. 15 is removably connected to a cuff 6 via a wire. The
cuff 6 is removably connected to a female connection cuff 7 of a
conduit. The connection cuff 7 comprises electrical mating pins for
connecting to the internal and/or external and/or integrated
conduit wiring. This internal and/or external and/or integrated
conduit wiring is then passed over the conduit to male connection
cuff 9 of the conduit, at the other end of the conduit. The male
connection cuff has male pins, which are designed to connect to any
other respiratory part of the respiratory system, such as for
instance another female connection cuff or a controller.
[0261] The HMI 5 can for instance be used to turn certain parts of
the respiratory system, such as humidifier system, flow generators,
heated hoses, or the entire respiratory system on or off. The HMI 5
can be located on any part of the respiratory system such as a
respiratory mask, a cuff, a hose, or on any other additional
equipment, such as a bed or a pillow, or may even be located in
another room. The HMI interface is preferably located near the
patient such that it enables the patient to segment their
treatment. It may be the case that for some reasons the patient is
bed bound and thus has to have the treatment continuously. It may
be the case that the patient needs different levels of treatment
during the course of the day/night. With the appropriate sensors it
will be possible for the controller to determine sleep patterns and
adjust the equipment accordingly. It may be the case that patients
don't want the hose to be heated continuously the patient may
require different temperature settings and these can be adjusted
automatically via ambient tracking or can be adjusted with the HMI
5. Another advantage of the HMI in combination with the
interconnecting conduit is that the flow generator and or
humidifier can be located further away from the patient, and thus
noise reduction techniques can be used and thus improving patient
comfort. To reduced noise the unit could be located in a cabinet,
which may perform a number of different tasks. Firstly it can be
used to reduce the noise, and light form disturbing the patient.
Secondly the cabinet could be used to improve and stabilize the
ambient conditions for the humidifier/flow generator.
[0262] The HMI 5 can for instance be used to initiate an alarm
function. It is for instance possible that a patient is bed bound
and needs help from another person. The HMI 5 could be used to
initiate an alarm function on the controller or any other
associated piece of equipment. The HMI 5 could be used to reset
certain alarm functions with associated pieces of equipment. It may
be the case that an alarm function has been tripped, for example
over temperature, lack of airflow etc. In the event of an alarm
function the HMI can be used to reset and restart the
equipment.
[0263] The HMI 5 could be used to adjust the operating conditions
such as flow pressure, temperature, humidity levels, and if
required control the administering of any associated medicines that
might be connected to the respiratory system.
[0264] The HMI 5 can use the respiratory conduit wiring systems to
communicate with associated equipment, or can use wireless
technology such as infared, radio, bluetooth. Usually, the wiring
requirements for the HMI 5 control functions will be lower than
those needed for the heating wires. The HMI could if required
utilize very low voltages such as 5V. Using lower voltages reduces
the wire sizes and increases patient safety. The HMI 5 can be
mobile allowing medical practitioners operating respiratory system
parts from another room. The HMI 5 can receive signals to indicate
equipment performance such as temperature, alarm functions, water
levels etc.
[0265] FIG. 16 shows a humidifier chamber of a humidifier system.
The humidifier chamber is thermally insulated from ambient
conditions. The insulation is done with a double walled chamber
construction 25 which comprises a cavity which is filled with air,
but may be filled with any insulating material such as a foam.
[0266] FIGS. 17-21 show different 4 wire circuit that may be used
in a conduit according to any aspect of the present invention.
[0267] FIG. 17 shows a standard 24VDC circuit. The circuit
comprises two heater wires for heating the breathable gas to be
passed to the patient, and two signal wires provided for
transferring the measurements of the at least one sensor. The at
least one sensor as shown in FIG. 17 is a thermistor, but may be
any type of sensor considered suitable by the person skilled in the
art. Due to the fact that four wires can be used, the heating
circuit and the temperature measuring circuit can operate
independently. The circuit shown in FIG. 17 further has the
advantage that the sensor may be monitored continuously.
[0268] FIG. 18 shows another standard 24VDC circuit. The circuit
comprises two heater wires for heating the breathable gas to be
passed to the patient, and two signal wires provided for
transferring the measurements of the at least one sensor. The at
least one sensor as shown in FIG. 18 comprises a thermistor as well
as sensor. A second sensor can for instance be used as a HMI. Due
to the fact that four wires can be used the heating circuit and the
temperature measuring circuit can be operated independently. The
second circuit with the use of a diode can also contain two
sensors, either one of which could be a HMI.
[0269] FIG. 19 shows another standard 24VDC circuit. Due to the
fact that four wires can be used the heating circuit and the
temperature measuring circuit can operate independently. In the
heating circuit there is now a diode and an additional sensor. The
remainder of the circuit is the same as that of FIG. 18.
[0270] FIG. 20 shows another standard 24VDC circuit. Due to the
fact that four wires can be used the heating circuit and the
temperature measuring circuit can operate together. In the heating
circuit there are now two diodes and an additional sensor, and now
between the two circuits that is also a diode and a further sensor.
This shows that using the four wire configuration it is possible to
have four sensors.
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